U.S. patent application number 11/460816 was filed with the patent office on 2007-06-21 for structures and processes for controlling access to optical media.
Invention is credited to Anoop Agrawal, Paul Atkinson, John P. Cronin, Rick Marquardt, Steve Parsons, John H. Rilum, Juan Carlos Tonazzi Lopez.
Application Number | 20070143774 11/460816 |
Document ID | / |
Family ID | 37709248 |
Filed Date | 2007-06-21 |
United States Patent
Application |
20070143774 |
Kind Code |
A1 |
Agrawal; Anoop ; et
al. |
June 21, 2007 |
STRUCTURES AND PROCESSES FOR CONTROLLING ACCESS TO OPTICAL
MEDIA
Abstract
An optical disc is provided with an associated optical shutter.
In a first state, the optical media interferes with the ability of
an interrogating laser beam to read data from the optical media,
and in a second state, the optical media is substantially
transparent, enabling the laser beam to read the disc. A powering
circuit is used to cause the optical shutter to transition from a
first state to the second state. In one example, an integrated
circuit acts as the powering circuit, as well as providing logic
and processing functions. The integrated circuit also couples to an
RF antenna, enabling the integrated circuit to communicate with an
associated RF scanning device. The optical shutter may take various
geometric shapes, and typically has an electrochromic material for
facilitating state change. The electrochromic material may fill the
shutter, or the material may form a pattern. The shutter may be
positioned on the disk so that transition edge-effects are reduced,
allowing for reduced interference with the laser beam when the
optical shutter is in its clear state. The optical shutter does not
cover the entire data area of the disc, and in one example, the
optical shutter is quite small, allowing for lower cost production,
as well as reducing power requirements to transition the
electrochromic material. Power requirements may be further reduced
by forming the electrochromic in a pattern. A small optical shutter
may disable reading of disc, for example, by placing the small
shutter over an important section of the disc, such as the lead-in
area.
Inventors: |
Agrawal; Anoop; (Tucson,
AZ) ; Rilum; John H.; (Tustin, CA) ; Cronin;
John P.; (Tucson, AZ) ; Tonazzi Lopez; Juan
Carlos; (Tucson, AZ) ; Atkinson; Paul; (Poway,
CA) ; Marquardt; Rick; (Clarcksummit, PA) ;
Parsons; Steve; (Dover, NH) |
Correspondence
Address: |
WILLIAM J. KOLEGRAFF
3119 TURNBERRY WAY
JAMUL
CA
91935
US
|
Family ID: |
37709248 |
Appl. No.: |
11/460816 |
Filed: |
July 28, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60703673 |
Jul 29, 2005 |
|
|
|
60720986 |
Sep 27, 2005 |
|
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|
Current U.S.
Class: |
720/738 ;
G9B/20.002; G9B/23.005; G9B/23.087 |
Current CPC
Class: |
G11B 23/0028 20130101;
G02F 1/1508 20130101; H01Q 1/44 20130101; G11B 23/286 20130101;
H01Q 1/2208 20130101; G11B 20/00927 20130101; G11B 7/252 20130101;
G02F 1/1524 20190101; G11B 20/00086 20130101; G11B 23/0042
20130101; G11B 7/24038 20130101; G11B 20/00608 20130101; G11B
23/282 20130101; G11B 20/00876 20130101; H01Q 1/40 20130101; G11B
23/0035 20130101; G02F 1/15165 20190101; G11B 20/00666 20130101;
G11B 7/24033 20130101; G11B 2220/2537 20130101 |
Class at
Publication: |
720/738 |
International
Class: |
G11B 23/03 20060101
G11B023/03 |
Claims
1. An optical media comprising: a disc having a data area; an
optical shutter in a geometric shape; and wherein the optical
shutter is on less than the full data area of the optical
media.
2. The optical media according to claim 1, wherein the disc further
comprises a lead-in area, and at least a portion of the optical
shutter is positioned in the lead-in area.
3. The optical media according to claim 1, wherein the total area
of the optical shutter is substantially less than the total area of
the data area.
4. The optical media according to claim 1, wherein the total area
of the optical shutter is less than 10% of the total area of the
data area.
5. The optical media according to claim 1, wherein the total area
of the optical shutter is less than about 1% of the total area of
the data area.
6. The optical media according to claim 1, wherein the total area
of the optical shutter is less than about 0.1% of the total area of
the data area.
7. The optical media according to claim 1, wherein the total area
of the optical shutter is less than about 50 mm.sup.2.
8. The optical media according to claim 1, wherein the total area
of the optical shutter is less than about 10 mm.sup.2.
9. The optical media according to claim 1, wherein the optical
shutter comprises electrochromic material.
10. The optical media according to claim 9, wherein the
electrochromic material substantially fills the area of the optical
shutter.
11. The optical media according to claim 9, wherein the
electrochromic material fills less than the area of the optical
shutter.
12. The optical media according to claim 12, wherein the geometric
shape is selected from the group consisting of diamond, square,
rectangle, circle, triangle, and irregular.
13. An optical media comprising: a disc having a data area; an
optical shutter in a geometric shape; electrochromic material
forming a pattern in the optical shutter; and wherein the optical
shutter is on less than the full data area of the optical
media.
14. The optical media according to claim 13, wherein the disc
further comprises a lead-in area, and at least a portion of the
electrochromic material is positioned in the lead-in area.
15. The optical media according to claim 13, wherein the total area
of the electrochromic material is substantially less than the total
area of the data area.
16. The optical media according to claim 13, wherein the total area
of the electrochromic material is less than 10% of the total area
of the data area.
17. The optical media according to claim 13, wherein the total area
of the electrochromic material is less than about 1% of the total
area of the data area.
18. The optical media according to claim 13, wherein the total area
of the electrochromic material is less than about 0.1% of the total
area of the data area.
19. The optical media according to claim 13, wherein the total area
of the electrochromic material is less than about 50 mm.sup.2.
20. The optical media according to claim 13, wherein the total area
of the electrochromic material is less than about 10 mm.sup.2.
21. The optical media according to claim 13, wherein the total area
of the electrochromic material is less than about 5 mm.sup.2.
22. The optical media according to claim 13, wherein the total area
of the electrochromic material is less than about 2.5 mm.sup.2.
23. The optical media according to claim 13, wherein the pattern is
a set of substantially parallel bars.
24. The optical media according to claim 23, wherein the bars are
substantially perpendicular to a data track on the disc.
25. The optical media according to claim 22, wherein the bars form
an angle greater than 90 degrees relative to a data track on the
disc.
26. The optical media according to claim 13, wherein the pattern is
irregular.
27. The optical media according to claim 13, wherein the geometric
shape is selected from the group consisting of diamond, square,
rectangle, circle, triangle, and irregular.
28. An optical media comprising: a disc having a data area; a
plurality of optical shutters positioned on the disc; and wherein
the aggregate area of the optical shutters is on less than the full
data area of the optical media.
29. The optical media according to claim 28, wherein the disc
further comprises a lead-in area, and at least a portion of at
least one of the optical shutters is positioned in the lead-in
area.
30. The optical media according to claim 28, wherein the aggregate
area of the optical shutters is substantially less than the total
area of the data area.
31. The optical media according to claim 28, wherein the aggregate
area of the optical shutters is less than 10% of the total area of
the data area.
32. The optical media according to claim 28, wherein the aggregate
area of the optical shutters is less than about 1% of the total
area of the data area.
33. The optical media according to claim 28, wherein the aggregate
area of the optical shutters is less than about 0.1% of the total
area of the data area.
34. An optical media comprising: a disc having a reading track; an
optical shutter on the disc; a transition edge on the optical
shutter; and wherein transition edge forms an angle with the
reading track on the optical media.
35. The optical media according to claim 34, wherein the optical
shutter has a transition edge, and the transition edge forms a
large angle with the reading track on the optical media.
36. The optical media according to claim 34, wherein the optical
shutter has a transition edge, and the transition edge forms a
small angle with the reading track on the optical media.
37. The optical media according to claim 34, wherein the optical
shutter has a transition edge, and the transition edge forms a
substantially perpendicular angle with the reading track on the
optical media.
38. The optical media according to claim 34, wherein the optical
shutter has electrochromic material arranged in a pattern, and the
pattern has a transition edge, and the transition edge forms a
small angle, a large angel, or a substantially perpendicular angle
with an information track on the optical media.
39. The optical media according to claim 34, wherein the
transitional edge is tapered.
40. The optical media according to claim 34, wherein the
transitional edge is a step-wise taper.
41. A method for interfering with the operation of an optical
laser, comprising: receiving a laser beam at an optical media;
distorting the laser beam at a transition edge to an optical
shutter; distorting the laser beam at a transition edge to
electrochromic material in the optical shutter; and distorting the
laser beam with the electrochromic material.
42. The method according to claim 41, wherein when the
electrochromic material is in its colored state, the aggregate
distortion is sufficient to cause the optical media to be unusable
by the optical laser.
43. The method according to claim 41, wherein when the
electrochromic material is in its bleached state, the aggregate
distortion is not sufficient to cause the optical media to be
unusable by the optical laser.
Description
RELATED APPLICATIONS
[0001] This application claims priority to U.S. patent application
No. 60/703,673, filed Jul. 29, 2005, and entitled "Devices for
Optical Media", and to U.S. patent application No. 60/720,986,
filed Sep. 27, 2005, and entitled "Devices and Processes for
Optical Media", both of which are incorporated by reference as if
set forth in their entirety. This application is also related to
U.S. patent application No. ______, filed ______, and entitled,
"Stable Electrochromic Device", which is also incorporated by
reference.
FIELD OF THE INVENTION
[0002] The present invention relates to an integrated circuit
device and electro-optical materials that cooperate to enable
selective access to content stored on an optical media. In one
example, the present invention provides a method and system for use
of an optical device to reduce theft of optical media, deny or
enable access to content stored within or on optical media, and for
communicating an aspect of optical media via perceptible means.
BACKGROUND OF THE INVENTION
[0003] An optical device, as the term is used herein, affects the
ability of either man or machine to perceive or access some aspect
of an optical medium. For example, an optical device may make media
such as a compact disc (CD), digital versatile disc (DVD) or a
high-definition disc (e.g., HD-DVD, Blu-ray Disc) readable or
non-readable by blocking, reflecting, deflecting, polarizing,
focusing, defocusing, changing the spatial or temporal phase
magnitude, affecting the spectral response, inducing a wavelength
change of, or otherwise disrupting or interfering with the
interrogating light source. In a similar way an optical device may
limit or control the recording access of an optical recording or
rewritable medium such as a CD-R, CD-RW, DVD-R, or DVD-RW by
affecting the recording light source.
[0004] Devices to affect the perceptibility of optical media are
commonly implemented in configurations in which the device is
separate and set apart from the optical media and rather a part of
the readout or recording hardware. For instance, mechanical devices
can be used to turn on or off the access of a playback or record
beam to an optical medium. More elaborate devices can be employed
to modify the interrogating optical readout beam in a playback or
retrieval device to gain access to optical media with distinctly
different resolution requirements (e.g. a CD/DVD switchable
player).
[0005] It is, however, desirable from both business and hardware
compatibility reasons to incorporate an optical device with the
optical media as one entity and for the optical device to be
switchable by electrical means, allowing for easy integration of
logic components for controlling access and security of the optical
medium. As detailed in U.S. patent Ser. No. 10/632,047, filed Jul.
31, 2003 and published as U.S. 2004/0022542, such an approach
allows for implementation of, for instance, a secure movie rental
scheme in which the underlying optical medium is a DVD. Another
example detailed in U.S. patent Ser. No. 10/874,642, filed Jun. 23,
2004 and published as U.S. 2004/0257195, allows for
denial-of-benefit security; a method of reducing theft of objects
by effecting the utility of the object in a way that diminishes its
value, and hence the incentive to steal it, until it is paid for
and at which time its utility is restored. In some applications it
is desirable and even required that the optical device can be
switched from one state to another (e.g. non-readable to readable)
only once. In other applications it is desirable or even required
for that the optical device can be reversibly switched in a
repeatable manner between at least two stable states, one state in
which the optical medium is accessible and a second state in which
the optical medium cannot be accessed. Furthermore, when the
optical device and optical medium are properly designed, access to
the content through the optical media should be equivalent or
similar to that when no optical device is present, so that
modification of the retrieval and/or recording hardware (e.g. the
DVD player) is not required. For a given or selected format, such
as that of DVD, the optical device-enhanced medium could then be
compatible with a large installed base of retrieval or recording
hardware.
[0006] Of particular interest are optical devices that are
electrically activated using systems and methods described in U.S.
patent application Ser. No. 10/874,642, filed Jun. 23, 2004 and
published as U.S. 2004/0257195.
SUMMARY
[0007] Briefly, the present invention provides an optical disc with
an associated optical shutter. The optical shutter has at least two
states. In a first state, the optical media interferes with the
ability of an interrogating laser beam to read data from the
optical media, and in a second state, the optical media is
substantially transparent, enabling the laser beam to read the
disc. A powering circuit is used to cause the optical shutter to
transition from a first state to the second state. In one example,
an integrated circuit acts as the powering circuit, as well as
providing logic and processing functions. The integrated circuit
also couples to an RF antenna, enabling the integrated circuit to
communicate with an associated RF scanning device. The optical
shutter may take various geometric shapes, and typically has an
electrochromic material for facilitating state change. The
electrochromic material may fill the shutter, or the material may
form a pattern. The shutter may be positioned on the disk so that
transition edge-effects are reduced, allowing for reduced
interference with the laser beam when the optical shutter is in its
clear state. The optical shutter does not cover the entire data
area of the disc, and in one example, the optical shutter is quite
small, allowing for lower cost production, as well as reducing
power requirements to transition the electrochromic material. Power
requirements may be further reduced by forming the electrochromic
in a pattern. A small optical shutter may disable reading of disc,
for example, by placing the small shutter over an important section
of the disc, such as the lead-in area.
[0008] In one example, the optical shutter is less than 50mm in
total area, although larger or smaller shutters may be used
depending on application requirements. The shutter is positioned
over the lead-in area of a disc, and distorts the interrogating
laser such that the disc player is unable to read the lead-in
information. Since this area contains important information
regarding the overall content of the disc, the player is not able
to effectively read the disc. It will be understood that the
shutter may be placed in other positions to obtain desired
distortion effects. Further, electrochromic (EC) material may be
patterned within the shutter, and the shutter and EC material
arranged to sufficiently distort the laser when the shutter is in
the dark state. In this way, less EC material may be used, enabling
faster transitions with less power.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a schematic cross section of an optical disc in
accordance with the present invention.
[0010] FIG. 2 is a block diagram of an EC device stack in
accordance with the present invention.
[0011] FIG. 3 is a block diagram of an EC device stack in
accordance with the present invention.
[0012] FIG. 4 is a block diagram of an EC device stack in
accordance with the present invention.
[0013] FIG. 5 is a block diagram of an EC device stack in
accordance with the present invention.
[0014] FIG. 6 is a block diagram of an EC device stack in
accordance with the present invention.
[0015] FIG. 7 is a diagram of an optical disc with an EC device in
accordance with the present invention.
[0016] FIG. 8 is an enlarged view of the EC device of FIG. 7.
[0017] FIG. 9 is a diagram of an optical disc with an EC device in
accordance with the present invention.
[0018] FIG. 10 is diagram of masks for disposing an EC device in
accordance with the present invention.
[0019] FIG. 11 is a diagram of an EC device layered in accordance
with the present invention.
[0020] FIG. 12 is a graph showing % transmission versus wavelength
for an EC material in accordance with the present invention.
[0021] FIG. 13 is a graph showing % transmission versus wavelength
for ITO and IZO in accordance with the present invention.
[0022] FIG. 14 is a block diagram of an EC device stack in
accordance with the present invention.
[0023] FIG. 15 is a diagram of an optical disc with an EC device in
accordance with the present invention.
[0024] FIG. 16 is a graph showing transition timing for an EC
device in accordance with the present invention.
[0025] FIG. 17 is a graph showing transition timing for an EC
device in accordance with the present invention.
[0026] FIG. 18 is a graph showing transition timing for an EC
device in accordance with the present invention.
[0027] FIG. 19 is a photograph of an EC Device in accordance with
the present invention.
[0028] FIG. 20 is a graph showing error rate for a disc using an EC
device in accordance with the present invention.
[0029] FIG. 21 has a set of shapes and densities for an EC device
in accordance with the present invention.
[0030] FIG. 22 is a diagram showing edge effects for an EC device
in accordance with the present invention.
[0031] FIG. 23 has a set of shapes and densities for an EC device
in accordance with the present invention.
DETAILED DESCRIPTION
[0032] Certain embodiments as disclosed herein provide for optical
devices and optical devices configured in optical discs. After
reading this description it will become apparent to one skilled in
the art how to implement the invention in various alternative
embodiments and alternative media. For instance, it can be
appreciated that the teachings of the optical disc in the present
invention may also be applied to other types of perceptual media
such as an optical disc containing multiple information layers, a
hologram, a holographic memory storage device, or printed material.
However, although various embodiments of the present invention will
be described herein, it is understood that these embodiments are
presented by way of example only, and not limitation. As such, this
detailed description of various alternative embodiments should not
be construed to limit the scope or breadth of the present invention
as set forth in the appended claims.
Optical Device:
[0033] An optical device may be constructed using thin films or
gels or other materials typically layered or otherwise organized in
ways that achieve their desired qualities such as rendering the
perceptual (optical) medium accessible or non-accessible by
blocking, unblocking, reflecting, polarizing, deflecting, focusing,
defocusing, changing the spatial or temporal phase magnitude,
affecting the spectral response, inducing a wavelength change of,
or otherwise disrupting or interfering with the interrogating light
source used for interrogating or recording in the optical media.
Furthermore the optical device may e.g. be switchable in a
repeatable manner between two stable states: an "open" accessible
state and a non-accessible "off" state. Additional intermediate
states may also be conceived in which only part of the optical
media can be accessed (e.g. defocusing or inducing spherical
aberration in the interrogating light beam such that only one of
some of the otherwise accessible layers of the optical medium can
be accessed).
[0034] The optical devices of particular interest are those whose
optical properties change in response to electrical signals and in
particular electro-optic devices such as electrochromic (EC)
devices. Examples of other electrically activated or switchable
devices include: liquid crystals, polymer dispersed liquid
crystals, dispersed particle systems, cholesteric liquid crystals,
polymer stabilized cholesteric texture liquid crystals. Other
examples of electro-optic devices which may also be employed use
materials that show a change in refractive index (e.g., potassium
dihydrogen phosphate (KDP), ferroelectric materials such as lead-
lanthanum-zirconium titanate (PLZT), lithium titanate, barium
titanate, polyvinylidene fluoride,) and those employing nanocrystal
(or quantum dot) structures and particles where transitions are
induced by electrical stimulation. Preferred optical devices have
multilayer construction with at least two electrically conductive
layers. Although the descriptions herein primarily use
electro-chromic examples, it will be appreciated that other
electro-optic materials may be used.
[0035] The materials used in the manufacture of the optical device
may be produced or disposed using conventional film/material
deposition processes ranging from sputtering, e-beam, and thermal
evaporation to chemical vapor deposition or wet chemical deposition
such as printing. In another example, one or more of the materials
may be disposed using liquid ink-jet processes. These materials
form an electro optical film or stack that may be assembled
directly onto the optical media or an element thereof (e.g. a disc
substrate) or a separate substrate, carrier, or tape for
integration with the optical media. As discussed later, the
electrically switchable optical device may also be combined with
other optical layer or devices that switch from an exposure to
stimuli other than electrical stimulus such as heat and radiation
(including optical radiation).
Optical Disc and Placement of Optical Device:
[0036] The method and means described herein are applicable to a
variety of optical media and in particular a variety of optical
disc configurations including, but not limited to single and dual
or more layers, single and double sided, and symmetrical and
asymmetrical configurations (e.g. single sided, single layer DVD-5s
and dual layer DVD-9s, double sided DVD-10s and DVD-18s, compact
discs (CDs) and the high-definition formats HD-DVD and Blu-ray
Disc. The DVD substrates or any other optical media such as
holographic media are made from clear plastic materials, for
example, polycarbonate. Other materials such as acrylics (e.g.,
polymethylmethacrylate) and cyclic polyolefins may also be
used.
[0037] FIG. 1 shows a schematic cross-section of a DVD 10, known as
a DVD-9, which has two substrates 12 and 14, typically made of
transparent polycarbonate, each of which is about 0.6 mm thick and
comprises a data layer (also known as data encoding or information
layer) shown as 15 and 16. The disc is made by bonding two
substrates (Substrate 1 (14) and Substrate 2 (12) with a
ultra-violet (UV) curable bonding agent. The reading laser accesses
the DVD from the readout side (18) as shown. Prior to bonding,
Layer L0 (16) is coated with a semi-reflective material (e.g. a
thin layer of gold or silver) (19) and Layer L1 (15) is coated with
a reflective material (21) (e.g. a thin layer of aluminum). The
reflectivities of L0 and L1 as well as the transmission of L0 are
balanced to achieve comparable levels of overall reflectivity from
each layer as seen by the interrogating laser beam from the readout
side. By focusing the laser beam onto each layer the corresponding
data layer can be accessed. Typically the thickness of the gold or
silver applied to L0 is in the range of 5 to 20 nm and of aluminum
applied to L1 in the range of 30 to 80 nm. The thickness of the
bonding layer (23) is about 50 microns.
[0038] It is proposed that an electrooptic (EO) device (see 25 in
FIG. 1), be located in or on the DVD so that such an EO device can
be activated to effect changes in one or more of its optical
properties and in particular to switch between colored or bleached
states. These devices in the bleached state (or open state) would
allow the laser beam access to the data layers and in the colored
or dark (or blocking or closed) state would interfere with the
transmission of the laser beam (e.g., by absorbing, reflecting,
diffracting or combinations thereof) so that in at least one of the
data layers the data area covered by this EO device is not
readable. A preferred EO device is an electrochromic (EC)
device.
[0039] As an example, the EC device would be colored for as long as
the DVD or any other equivalent optical media, sits on the shelf of
a retailer. When it is legitimately purchased by an end-user the
retailer would effect an action whereby the EC device is altered or
bleached thus allowing the content to be accessed (the disc made
playable). This action, or "activation" is preferably conducted
wirelessly, e.g., see U.S. Patent Publication 2004/0022542, which
is incorporated herein by reference.
[0040] The EC device may be positioned such that it is between the
interrogating laser and the data layers to which access is being
enabled or denied. For example, the EC device may be positioned in
the region between the two data layers (L0 and L1) where it would
prevent the laser from reading data on L1. The EC device may also
be located between L0 and the readout side of Substrate 1 to
prevent both L0 and L1 from being read. In a single layer disc, the
data layer can be located in substrate 2, e.g., data layer L1, and
the EC device can be positioned similarly to that of a L1 in a
DVD-9. There are also alternative multi-layer disc configurations
and methods of bonding, in which L0 is placed on a third, very thin
substrate (substrate 3) which is bonded to substrate 2 (on top of
L1), and upon which Substrate 1 is subsequently bonded. In such a
configuration, the EC device could be located in-between L0 and the
readout side (e.g. on top of L0).
[0041] In particular constructions of the optical disc, one or more
metal layers within the body of an optical disc (as shown by gold
and aluminum layers, L0 and L1 respectively) are used as elements
(electrodes) of the EC device. Also disclosed are examples of an EC
device located relative to the metalized data layer or layers in an
optical medium. Example EC devices may also be formed on a
substrate which may then be integrated with the DVD. The substrate
with the EC device may also have electronic components and antennas
integrated on to either side of the substrate. This substrate may
be integrated within the DVD, e.g., between the two halves of
DVD-9, DVD-10, DVD-18, HD-DVD etc. or on the surface of the
air-incident side of a finished DVD so that it is able to interrupt
the reading laser beam when desired. In the later example, the
substrate may be bonded to the disc using for example, a UV curable
adhesive. The entire surface of the disc, including the bonded
substrate may then be coated with a hard, scratch-resistant coating
(e.g. UV lacquer). Also disclosed are attributes of the EC devices
which are suitable for this purpose. Further disclosure is given of
methods and processes to form and integrate these devices on the
optical media. In some constructions devices are discussed having
mixed or multiple functionality where more than one mechanism is
used to change the state of the optical devices.
[0042] In cases where the optical device uses a separate substrate,
the substrate may be flexible or rigid and may or may not include
an adhesive, such as a PSA (pressure sensitive adhesive) material
or other material to assist in the process of bonding the optical
device to the disc. One or more EC devices, with electronic
components and antennas as appropriate, may be assembled on a
single item of substrate. For example, EC devices may be assembled
along a continuous reel of flexible substrate in a continuous web
process or in rows and columns on large sheets of rigid substrate,
such as ultrathin glass or a thermoplastic or a thermoset plastic.
The electronic components may be positioned using pick-and-place
manufacturing processes and the antennas may be screened, printed,
ink-jetted or deposited to the substrate. The fully constructed
substrate, including electronic components and antenna as
appropriate, may be stored as assembled on continuous reels or
sheets or cut into individual units.
[0043] Individual substrates may be placed in the appropriate
position relative to the disc using mechanical means (e.g. a
pick-and-place machine). Substrates on continuous reels may be
rolled directly onto the medium if e.g. using an adhesive
substrate. Alternatively the disc can be furnished with a curable
polymer/lacquer (e.g. hot melt of UV curable) or optical quality
cement before the optical shutter assembly is applied. To maintain
an overall thickness consistent with the appropriate specifications
(E.g. DVD, HD-DVD or Blu-ray) and industry norms, and to insure
compatibility with reading devices and players, the disc may be
manufactured (e.g. molded) slightly thinner to accommodate the
additional thickness of the EC device and its substrate and surface
coating if appropriate.
[0044] Some of the substrates to form these devices are made of
polycarbonate, polyester (e.g., polyethyleneterephthalate and
polyethylenenaphthalate) polycycloolefins and acrylic (e.g.,
polymethylmethacrylate) polymers in a thickness of less than 0.3 mm
(preferably 1 n the 20 to 150 micron range), and ultrathin glass in
a thickness of less than 200 .mu.m (preferably 20 to 60 micron
range). A preferred polycarbonate product is an extruded film
called Europlex.RTM. PC from Degussa, Germany, of which a specific
example is grade OF405. Ultrathin glasses for example are available
from Corning (Corning, N.Y.) as Microsheet Glass and from Schott
Glass (Mainz, Germany) as D263T and AF45 glasses. If the external
integration method is used, the substrate surface area and shape
may be as big as the DVD, or it may be smaller. A disc shaped
substrate may also have protruding areas from the perimeter where
the device may be located. The optical disc (e.g. DVD or HD DVD)
may also be molded with indentations on their external surfaces
shaped similarly to the substrate and any components mounted to it,
to allow the substrate to be housed and bonded seamlessly in this
indentation and thus maintain the disc's original form. For
external integration using polymeric films one may pre-coat these
with a hard coating, or a hard coating may be deposited after the
film is integrated with the disc. The hard coats such as silica,
silica and aluminum nitrides may be deposited using physical or
chemical vapor deposition, or hard coats may be deposited by a
wet-chemical deposition. One preferred method is by spin coating
after the film is bonded to the disc.
[0045] An alternative is to form, dispose, or assemble the
electro-optic device and other components on the disc itself. Yet
another alternative may be to form, dispose, or assemble some of
the components on the disc (e.g., EO device and the chip) while the
other components (e.g., antenna) are assembled on a different
substrate and then connected to the components on the disc. In the
latter case the antenna may be removed by the end-user before
playing the disk. The removable antenna may be affixed to printed
lines on the surface of the disk using "Z axis conductive"
adhesive. A Z axis conductive tape has conductive paths that allow
antenna signals to be passed through the conductive tape, while
avoiding shorts between paths. In this way, an antenna may be
adhered to a set of antenna contacts on the disc, with the tape
providing sufficient electrical connections between the contacts
and the antenna. These are anisotropic conductors which only
conduct in their thickness direction and are typically sold as
tapes which are thermosets or thermoplastics (including pressure
sensitive tapes). As examples these are available from Btech
Corporation (Longmont, Colo.) as ACF film and 3M Corp (Saint Paul,
Minn.) as tape 9703. An example construction for a dual layer disc
has the EC device positioned between these two metal layers and
configured such that one of these metal layers (e.g. either L0 or
L1) is used as an electrode in the EC device. For those DVDs which
have only one data layer (e.g., a DVD-5), the metal layer may also
be used as an electrode for the EC device. For those DVDs where
more than two data layers are used (e.g., a double-sided, dual
layer DVD-18) the EC device may use any of the metal layers as
electrodes. To achieve desired switching times, a preferred surface
resistance of the electrode layer is less than 100 ohms/square. As
an example the surface resistivity at about room temperature for a
20 nm thick gold electrode is about 1.1 ohms/square and that of 40
nm aluminum would be about 0.66 ohms/square.
Electrical and Optical Characteristics of the EO device
[0046] Several descriptions of the EC devices will be given below
which may be used for this purpose. More specific placement
configuration and geometry of the devices on DVDs will be discussed
later. Of particular interest are EC devices that do not require
any external power to maintain either their colored or their
bleached states. In this way, the EC device persistently maintains
the desired state. In some cases, the desired state may be a
persistent bleached state, and in other cases, a persistent colored
state may be desired. The length of the persistent state may be
defined according to application needs. As an example, the colored
state (i.e. time lapsed between DVD production and sold to end
customer) should be as long as possible, and the most preferred
state is forever, or at least for a commercially required period of
time. However, a minimum period for which this layer should remain
dark to prevent a DVD being operated is greater than three months
and a more preferred time period is greater than 3 years.
Similarly, once the DVD has been purchased the EC device should not
become dark or closed with time as this DVD will become unusable
and expire. For certain applications such as rentals, only a short
expiration period is required for the content to be accessible,
whereas for others such as a purchase, longer expiration periods
(or no expiration) are preferred. Thus the bleach period (open
period or time to expire) required for rental applications may be
only a few (e.g., four) hours to a few days (e.g. 2 days), whereas
for end user who purchase a DVD this period would be greater to
e.g. 2 years or preferably longer (e.g. 10 years or more). In
certain situations, e.g. in rental business, it may be desirable
for an expired DVD to be made operable again by bleaching the EC
device (e.g. at the rental agency). In another model for the rental
agency, the disk expires permanently so that the consumer may
discard the DVD after the expiration period rather than return this
back.
[0047] Limited duration use optical media has been discussed in
several publications such as U.S. Pat. Nos. 5,815,484, 6,011,772
and in 6,917,579 where a reactive layer is inserted before the
reading optical beam (e.g., a laser) accesses the data layer. The
optical properties of this reactive layer change upon a triggering
event (such as removal of a label or a package, exposure to light,
etc.) or simply change with time, particularly as this layer comes
in contact with diffusing moisture and or oxygen. The information
in these patents pertaining to processing, materials used,
positioning of materials used, etc., is all included herein by
reference. In all these cases the optical media goes from being in
an open state (meaning where data can be accessed) to a closed
state (where data cannot be accessed) as the optical properties of
the reactive layer or the active optical layer change. We disclose
a novel concept where the reactive layer or the optically active
layer is in the closed state, and it is opened for a limited time
to allow access to the data and then back to a closed state.
Alternatively, the open state of the device may also be configured
so that it remains open indefinitely (or as long as required for
the application) after it is activated.
[0048] For the purchase model, EC devices described below are
highly desirable. In such a purchase model, EC devices are
preferred that result in one way switch. In this way, the target
optical disc may be made unreadable at the time of manufacture,
remain unreadable as it progresses through the distribution chain,
and then be switched to a persistent readable state at the time of
authorized sale. Typically this is done by combining an EC state
chance with a non reversible reaction in the device. The
non-reversible reaction may support or effect the state change in
the EC material, and may be a chemical reaction activated
responsive to electrical stimulation. This chemical reaction may
result, for example, in persistent polymerization or
depolymerization, or in an irreversible chemical oxidation or
reduction. Examples of these will be provided later. Particularly
desirable are those EC devices which do not exhibit any meaningful
potential between the electrodes, either in the colored or bleached
state but only change the state when activated by an appropriate
voltage. Such devices can be stored in their desired states for a
long time without undesirable self discharge through the ion
conductor or an external circuit to which they are connected to. EC
devices known in the art have a substantial potential between the
two electrodes in at least one of the optical states. An EC device
is typically controlled or driven by an external circuit that
applies an electrical charge when a state change is desired.
Depending on circuit design, when the circuit is no actively
driving the EC material, the external circuit may present an
impedance between the two electrodes from a short to about 20
Mohms. When sufficient potential exists between electrodes, the
driving circuit will allow current to drain between electrodes,
thereby allowing the EC material to transition from its desired
state. Also if diodes (including surface diodes) are used in
external circuits then these diodes may be turned on by residual
potential in an EC device. If these diodes are turned on, then
current will flow, allowing the EC material to transition from its
desired state. A typical voltage range to turn on the diodes are
between 0.2 to 1V. To avoid activating the diodes, an EC device
should have a residual voltage in any of its optical states (usable
optical range for a particular application) to be less than 0.2V
and preferably close to 0 volts. A use of such device is discussed
below for optical media but these EC devices may also be used for
tamper resistant labels for a variety of products, displaying
product status as it moves down the manufacturing to retail chain,
displays, greeting cards, credit cards, and the like. In some
cases, unauthorized individuals may attempt to change the EC
material to its "on" state through tampering in an effort to
illegally gain access to the disc's content. For example, they may
subject the disc to temperature extremes, to humidly, to chemicals,
to shock, or to other stimulation. Therefore, it is desired that
the EC device remain stable even at elevated temperature, humidity
or when subjected to radiation (e.g., microwave, UV, solar
radiation, etc.), or common chemicals so that the tampering with
the EC device will not result in unauthorized access,. In cases
where extreme tampering may result in an unauthorized state change,
it may be desirable to permanently disable a disc when the disc is
tampered with by subjecting it to excessive temperature, chemical
exposure, or radiation. More generally, the EC device should remain
stable under normal usage conditions, which may include exposure to
temperate extremes, for example. Depending on the product and the
expected usage, these conditions could be defined. For many
consumer products typical high temperatures in excess of 60 or 85 C
for more than 1 to 10 hours would be very unlikely under normal
consumer abuse, and would tend to indicate intentional tampering.
In one example, optical stability for EC devices may be
demonstrated by 1) measuring voltage across the EC device
conductors, or 2) shorting the conductors and measuring how long it
takes for the EC device to transition away from the desired state.
These measurements may be taken in typical use conditions, which
may include expected temperature or environmental extremes. For
example, the voltage may be measured and the conductors shorted at
room temperature, and up to 80 C . It will be understood that other
temperatures and conditions may be used depending on the
application.
[0049] Known EC devices generally require external power to keep at
least one of its completely bleached or completely colored states
for prolonged periods. Otherwise, they relax or transition to one
of the optical states, called rest state. In one of the
configurations of the EC device, the device keeps its completely
colored state until activated, without any power consumption for
several years or preferably forever. It will be appreciated that it
may be acceptable to persistently hold the colored state for a time
period defined by commercial requirements, which may vary depending
on the specific application. Once the change is triggered this
device should go to its bleached (or open) state and forever allow
access to the data on the disc. It will be understood that the
length of time the EC device needs to remain persistently colored,
and the time the EC device needs to be persistently bleached, will
vary depending on the specific application. For example, it may be
acceptable for a particular DVD title to be persistently colored
for only the first 6 months after manufacture, because the bulk of
sales will be within the first few months. In a similar manner, it
may be acceptable that the EC device, after authorized change to
the bleached state, may be persistently held in the bleached state
for only 3 years, since the content will be out of date or
undesirable after that time period. It will be appreciated other
time periods may be selected.
[0050] In another configuration if the content of the media, e.g.,
DVD is rented for a short while, then the device should go to its
open state when triggered legitimately and then return to dark
state (or close) within a few hours or days (as desired by the
application) so that the data again becomes inaccessible. The
limited open time EC device can be designed using EC technologies
explained below. As in a battery, a limited-time reversible EC
device will typically have a potential between the two electrodes
when it is completely colored or completely bleached or in both
extreme states. When this potential exists in the colored state, it
will drive an internal reaction where most of the color may be
gradually lost over a period of time. One way to arrest this is to
reduce or eliminate this potential by choosing an EC material which
in its colored state has the same potential as the counterelectrode
or is at its natural rest state (this means 0 potential between the
two electrodes). For those EC devices that have potential in one of
the states (e.g., bleached state) the device will gradually
gravitate towards the colored state making the disk non-playable at
a threshold optical transmission value. Also, one may reduce the
electronic leakage between the two electrodes to keep the
coloration level for long/or desired amount of time. Electronic
leakage through the device can be controlled by the properties of
ion conductor. EC devices may be made with a leakage current of 10
.mu.A/cm2 to less than 1 nA/cm2 to give a limited open time. The
area refers to the area of the EC device. In this way, adjusting
the material composition to affect the leakages current enables
construction of discs that stay in a state for a predictable time
period. It will be appreciated that the time period may vary
depending on conditions, and that the time period is in part
dependant on the characteristics of the device attempting to read
the disc. For example, an EC device fading from its fully darkened
state to a more transparent resting state may by be readable in one
disc player before it is playable in a different disc player. In a
similar way, an EC device fading from its fully bleached state to a
more opaque resting state may by be readable in one disc player
longer than in a different disc player.
[0051] Transparency of the device should be in any optical region
of interest for a specific product, and at present, for DVDs the
wavelengths of interest are at about 650 nm, for high-definition
(high density) discs at about 405 nm, and for conventional compact
discs (CDs) at about 780 nm. It will be understood that other
wavelengths may be desirable depending on application specific
requirements.
Electrochromic (EC) Materials, Devices and Their Processing
[0052] There are several types of known EC materials which may be
used for providing selectable optical states. A description of
various standard EC materials is given in U.S. Pat. No. 6,493,128.
However, these EC materials as constructed using known processes,
need on-going power to maintain a desired state, or else they
transition to an undesirable rest stated. As described below, EC
materials are selected to interact with another material in an EC
stack, and when the EC material is in its desired long-term state,
the other material is in a highly stable condition. In this way,
there is almost no voltage across the EC device, so almost no
leakage current is generated. Therefore, the EC material remains in
its desired state persistently.
[0053] FIG. 1 shows a DVD 10 construction with dual layers. The two
substrates 12 and 14 are formed separately with molded in data
pits. The substrates and data pits are coated with metal layers 19
and 21 and then bonded. The EC device 25 may be located between the
two substrates as described below. An EC device may be constructed
where the two metal layers on the DVD are used as electrodes.
Depending on the type of EC device, the metal layers may be further
coated with EC and counterelectrode materials. The bonding material
may be replaced by an electrolyte or ion conductor. In another
design, only one of these metal layers is used as an electrode and
a thin film stack comprising another conductive layer may be
deposited to make a complete EC device. Example EC devices may use
a film stack approach using only one of the metal layers so that it
can be formed on one of the disc halves without complicating the
assembly and alignment of the two halves. When the EC device is
sandwiched between two conductive electrodes, and uses one of the
above described metal layer as an electrode, it is desirable that
the second conductive electrode in the stack be a transparent
conductor (TC). The layers of the device excluding metallic layers
(such as L0 and L1) should be highly transparent in the open state
and induce least distortion to the optical passage of the
interrogating optical beam.
[0054] FIG. 2 shows an example construction of a thin film device
25 that uses a metal layer 26 of the disc as an electrode and with
subsequently deposited layers of EC material 27, ion conductor 28
and counterelectrode 29, and an opposing transparent conductive
electrode 31. The metal layer 26 may be the same as one of the
metal reflective data layers L0 and L1 as shown in FIG. 1. The
device in FIG. 2 may also be fabricated by inverting the layer
sequence, where instead of EC layer, the counterelectrode 29 is
deposited on the metal 26, followed by the ion-conductor 28 and
then the EC layer 27.
[0055] Metal layer 26 may be made out of any metal or a reflective
layer which is optically useful for the DVD technology, and as long
as it is conductive and electrochemically compatible it could be
used as an electrode for EC. Other preferred metals are aluminum
alloys (including aluminum/titanium alloys), silver and its alloys,
rhodium, titanium, nickel, chromium, antimony and its alloys,
tantalum and stainless steel. Of these, preferred aluminum alloys
are 2000 series (with mainly copper), 5000 series (with mainly
magnesium), 6000 series (with mainly magnesium-silicide) and 7000
series (with mainly zinc). The percentage of the alloyed materials
is generally in the range of 0.5 to 3 atomic percent. In
aluminum/titanium alloys, the percentage of Titanium is in the
range of about 0.5 to 50%. There may also be other added alloying
elements in lesser quantities such as chromium, lithium, manganese,
titanium, zirconium, iron, lead and bismuth. The preferred alloys
of silver are with one or more of neodymium, palladium, gold and
platinum. The alloying elements in silver are usually added in a
range of less than 3 atomic percent. The preferred stainless steels
are 316, 304 and 430.
[0056] The conductive electrode layer may not be a single
reflective layer but rather it may be composed of several metal
layers or a combination of metal and transparent conductor layers.
Use of multiple layers avoid the corrosion and electrochemical
activity issues of the underlying layers while still being able to
use their electrical conductive characteristics. A multilayer
conductive electrode may be comprised of a transparent conductor
(TC) deposited over a metal layer. Examples of preferred
transparent conductors are doped tin oxide, doped indium oxide and
doped zinc oxide. Tin oxide may be doped with antimony or fluorine,
indium is usually doped with tin oxide (Indium-Tin Oxide (ITO)) or
with zinc oxide (called IZO) and zinc oxide is usually doped with
aluminum oxide. In ITO and IZO, the atomic percent of tin and zinc
is rather high, in the range of 5 to 20% for tin, in the range of
15-50% for zinc, whereas in the other cases the dopant
concentration is usually less than 5%. The resistivity of these
layers should be as small as possible and for optical media
applications less than 100 ohms/square is acceptable. Typically
these resistances can be achieved in coatings with a thickness of
50 nm or more, where a range of about 50 to 200 nm is preferred.
Organic conducting layers may also be used which may be formed
using conductive polymers, carbon nanotubes and polyhedrals. The
thickness of the metal layers is typically less than 50 nm and that
of the TC deposited on the metal is less than 200 nm, preferably
less than 100 nm. Multiple metallic layers are used where one of
the metal layers serves as adhesion promotion layer between the
plastic substrate and the next metal. Some of the adhesion
promotion metal layers are chromium and titanium in a thickness of
about 5-20 nm. For the purposes of illustrating the EC concepts
clearly, we will assume that all the EC devices are built after
depositing a gold layer on one of the polycarbonate disc substrates
(either L0 or L1) and that it will be used as one of the conducting
EC electrodes. The device concepts here can be adopted for
depositing them directly onto the Data layers, or on separate
substrates which are then integrated with the DVD. For those
devices which are formed separately and then integrated, it is
preferred that both of the electronically conducting layers of the
EC device are transparent. Further if this substrate is placed
between the two DVD halves, then it is preferred if the refractive
index of this is matched to that of the UV curing glue used to
assemble the two halves to within 0.2 and preferably within 0.02
units.
[0057] In FIG. 2, the EC layer 27 may be an inorganic oxide or a
polymeric material. Some of the preferred inorganic oxides comprise
of tungsten oxide, niobium oxide, prussian blue, molybdenum oxide,
nickel oxide, and iridium oxide and some of the preferred organic
polymers are polyaniline, polypyrrole, polyethylenedioxythiophene
(PEDOT), polyisothianaphthene and their derivatives. These
materials may be amorphous or crystalline. Alternatively, the EC
layer may be metallic, for example, aluminum, nickel, or other
metal. The ITO (TC) coating may also be used on top of the metal
layer as an EC electrode. The thickness of the EC electrode is
usually in the range of 100 to 500 nm. These layers may be reduced
by injecting them with protons, lithium, sodium, potassium and
silver ions along with electrons. The EC layers may also be
oxidized by removing these ions and electrons. Tungsten oxide,
niobium oxide, molybdenum oxide, polyisothianaphthene and PEDOT
color upon reduction whereas others e.g. polyaniline, nickel oxide
and iridium oxide color by oxidation. As discussed later one may
use both types of EC layers in a device by combining complimentary
EC materials i.e., the ones that color upon reduction and those
that color upon oxidation. When the device is bleached, both layers
bleach and when it is colored then both of the layers color.
Organic EC layers may also be formed by taking the organic ion
conductors described below and co-reacting or physically trapping
organic EC and/or redox materials, such as viologens, amines,
ferrocenes, ferrocenium salts, etc.
[0058] The ion conductors 28 in FIG. 2 are configured according to
the ions which are transported through the electrolyte medium. For
example, tantalum oxide is a good proton conductor and lithium
niobate, lithium tantalate, lithium silicate, lithium aluminum
fluoride and lithium-phosphorous oxynitride (LIPON) are good
lithium ion conductors. Sodium .beta. alumina is a good sodium
conductor and rubidium silver iodide and silver .beta. alumina are
good silver ion conductors. Polystyrene sulfonic acid or other
polymeric acid salts of sodium, lithium and potassium are able to
conduct either of protons, lithium, sodium and potassium
respectively. Some examples are sodium and lithium salts of
polystyrene sulfonic acid, polyacrylic acid, polyacrylic and maleic
acid copolymers, poly 2-acrylamido-2-methylpropane sulfonic acid
(polyamps), etc. Other polymers with sulfonic acid, carboxylic acid
moeities may also be used. The above polymers with acid groups
(i.e., without the salt formation) may also be used as proton
conductors. The conductors may be cation or anion conductors. The
thickness of the ion-conductors is about 10 to 5000 nm. Polymeric
ion conductors may also be made by adding salts, ionic liquids and
plasticers that solubilize salts to any crosslinking or
non-crosslinking polymers as long as these are compatible.
Compatibility can be easily gaged by transparency of the system, as
non-compatible systems will phase separate to a point that they
will be opaque or translucent. Such ion conductors may comprise of
polyether and polyimine moieties. Preferred polyethers are
polyethylene oxide and polypropylene oxide. End functionalized
polyethers could be employed to generate crosslinked networks of
ion conducting materials. Depending on the functionality
coreactants may be required. For example Vinyl, acrylic and
methacrylic end functionalities are typically used for curing by UV
and thermal processes. One may use coreactants to form urethane,
siloxane, epoxy, polyester or nylon bonds. As an example, if the
functional groups are polyols one may use isocyanates for forming
urethane networks. These will also comprise of appropriate
initiators and/or catalysts along with adhesion promoters, oxygen
scavengers, additional crosslinkers, etc. These EC devices may also
function by the movement of anions rather than cations. Thus the
ion conductors may be anionic, such as polymeric quaternary
ammonium salts with mobile anions such as trifluoromethylsulfonate
("triflate," CF3SO3-), bis(trifluoromethylsulfonyl)imide
(N(CF3SO2)2-), perchlorate ClO4-, bis(perfluoroethylsulfonyl)imide
((C2F5SO2)2N--)), tris(trifluoromethylsulfonyl)methide
((CF3SO2)3C--)), tetrafluoroborate (BF4-), hexafluorophosphate
(PF6-), hexafluoroantimonate (SbF6-), and hexafluoroarsenate
(AsF6-).
[0059] The counterelectrodes 29 may be complimentary to the EC
electrodes in terms of optical coloration or may show a little or
no optical change upon oxidation and reduction. In conventional EC
devices the purpose of the counterelectrodes is to store ions which
are injected into or ejected from the EC layer when a voltage is
applied across the electrodes 26 and 31. These electrodes are also
known as ion-storage electrodes. As an example in an EC device that
uses an EC layer that colors upon reduction one may use the
counterelectrode as another EC layer that colors upon oxidation.
Thus when the ions leave the counterelectrode this layer oxidizes
(and hence colors) whereas the EC layer also colors as the ions
enter this layer and it reduces. Examples of inorganic
counterelectrode (CE) materials that do not change their color upon
oxidation and reduction are, e.g., are titanium vanadium oxide and
cerium titanium oxide. Generally the thickness of counterelectrodes
is in the range of 100 to 500 nm. Each of the layers in the EC
device may be a single layer of one material or a composite of
multiple materials, or they may comprise of multiple layers of
different materials. The counterelectrodes may also be organic and
their nature oxidizing or reducing is typically opposite to that of
the EC electrode. For example a device using an EC electrode of
polyaniline which bleaches from a colored state to a bleached state
by reduction, would have a counterelectrode which can oxidize. Some
of the organic materials for this purpose may be phenazine and
hydroquinone and their derivatives. These materials may be
incorporated in a solid device by tying them covalently to a
polymeric backbone and/or incorporating them in a thermoplastic or
a thermosetting matrix. Preferred matrices are polymers which are
described in the ionic conductors above. This may be done to
increase the ionic conductivity of the layer for faster switching
devices. For example CE materials may be made, e.g., hydroquinones
mixed with ion conducting polymers as given above, and vanadium or
nickel oxide in Li--Al fluoride. Some examples of EC materials made
by combining ion conductors and EC materials are polyaniline with
polyamps, polymeric quaternary ammonium salts or with sodium salt
of polystyrene sodium sulfonate, polyacrilic acid and Nafion.RTM.,
etc. Another example would be tungsten oxide and molybdenum oxide
mixed in Li--Al fluoride.
[0060] The mobile ions, e.g., protons, lithium, sodium or silver
are introduced in the device by co-depositing these with the EC or
the counterelectrode (CE), or as a separate layer which is then
intercalated into the EC or the counterelectrode, or by chemical or
electrochemical reduction. The various layers in the EC device may
be deposited by physical vapor deposition (PVD), chemical vapor
deposition (CVD) or by wet chemical processing (spinning, dipping,
spraying, ink jet printing including patterning of solutions). PVD
includes reactive sputtering of metals, radio-frequency or pulsed
DC sputtering of non-conductors (e.g., oxides), thermal, laser and
e-beam evaporation. These processes may also be assisted by plasma
and ion treatments. Lithium is difficult to co-deposit by
sputtering or evaporation of lithium metal due to its high
reactivity. A preferred method is to use an alloy of lithium and
aluminum for evaporation or sputtering. This results in a
preferential removal of lithium from the target, and oxygen in the
processing chamber is bound by aluminum. In another alternative
tungsten oxide comprising oxide materials may be deposited by
sputtering in an argon atmosphere which leads to films in the
reduced (or colored) state.
[0061] Irreversibility or limited cyclability may be introduced to
the point of only allowing the device to change once before it
locks in the change permanently by several means. One may use a
counterelectrode which does not result in reversible change, e.g.,
zinc oxide, tin oxide, silica, alumina, etc., when intercalated
with protons or lithium or causing irreversible
chemical/electrochemical changes. The intercalated ions may be made
irreversible with time as they bind or react slowly within the host
layer. Since these materials are not known to intercalate these
ions, such ions may nevertheless be inserted by applying high
voltages, i.e. in excess of 2V and preferably in excess of 2.5V and
most preferably in excess of 3V. Most EC devices in this disclosure
will operate in the range of 0.8 to 6V. These will be called
ion-reactive layers as they react with the ions and then do not
release them.
[0062] The ion-reactive layers may be formed from organic and
organometallic materials. These ion-reactive layers may be used as
counterelectrodes or even as irreversible ion traps located between
the EC and the ion conductor layer. Silanes, such as epoxy silanes,
amino silanes, mercapto silanes, methyl tetraorthosilicate, etc.
may be used to form these layers. Silanes may be deposited from
about 1% solutions in ethanol or methanol. Water or acids may also
be added to pre-hydrolyse them. As an example this layer may be
added between the EC layer and the ion conductor or be substituted
with the ion conductor or be located between the counterelectrode
and the transparent conductor. It was found that when using
tungsten oxide as the EC layer, the silane coating allowed the ions
to go through to color the EC layer, but was more difficult to
bleach. Ion-reactive layers to trap lithium may also be made which
comprise of crown ethers. Crown ethers are molecules which have
cavities of just the right size to trap ions or molecules. Thus,
appropriate crown ether should be one that can trap lithium. A
crown ether suitable for trapping lithium has a cavity size of
about 0.085 nm such as 15-crown-5 (15C5) available from Sigma
Aldrich (Milwaukee, Wis.). To form a layer comprising crown ethers,
these crown ethers may be mixed with the silanes or introduced in
matrices of polyethylene oxide and/or polypropylene oxide or other
ion-conducting polymers described above. In one method
polypropylene glycol may be mixed with crown ether and a curing
agent based on an epoxy or an isocyanate. This mixture is deposited
by spin coating or other method and cured (e.g. cross-linked) into
a solid film. In some example constructions, formulations may be
made, which are UV cured, by using polypropylene glycols which are
terminated by methacrylic or acrylic groups (including epoxy and
urethane acrylates), adding UV initiators and curing them after
deposition. One may also use alternative formulations which are
solidified upon cooling (commonly called hot glue) or those
materials which are processed like hot glue to give immediate green
strength for handling, but can be further cured by UV or by
mechanisms using room-temperature vulcanizates (RTVs). For trapping
ions one may also use materials that get reversibly or irreversibly
reduced, e.g., peroxides, disulfides, manganates, chromates and
dichromates, etc, which may be also put in the matrices as are
crown ethers.
[0063] The development of an electrochromic device which is stable
in both the dark and bleached form requires a fine tuning of the
half cell potentials of redox species. The bleached oxidizing agent
and reducing agent must result in a cell potential of less than of
equal to zero. This can generally be calculated using the Nernst
equation. However, in the search for a device which is stable in
both the bleached and dark state the cell potential for the reverse
reaction must also be less than or equal to zero. Such a set of
oxidizing agent and reducing agents is required for such as
system.
[0064] An alternative approach to this system is to select either
the oxidizing agent or reducing agent to undergo an irreversible
reaction. This will prevent any possibility for the establishment
of a galvanic cell upon electrochemical switching. This will of
course produce a single use electrochemical device. Simple examples
would include chemical species which converted to gasses or are
precipitated upon undergoing the redox reaction. In an
electrochromic device such reactions are not practical, other
systems must be considered. Systems which undergo a chemical change
through the addition or removal of an electron are desirable. Such
systems may undergo dimerization or polymerization, add a ligand or
undergo a significant structural change.
[0065] Electrochemical polymerizations are generally employed to
produce conducting polymers. However, use of the monomers as the
reducing agent in an electrochemical cell should produce an
irreversible electrochemical device. Pyrroles, thiophenes, anilines
and furans have all been shown to undergo electrochemical
polymerization. The oxidizing potential of the monomer can be
controlled by relative electronegativity of the monomer. Careful
selection of the monomer will enable development of an electrolytic
cell where there is no possibility of forming a galvanic cell after
a potential has been applied.
[0066] Other possibilities involve a chemical change such as the
formation of bonds in the thiol to disulfide conversion. Others
would involve a geometric change in a metal complex, such as a
tetrahedral to octahedral change in geometry. Many examples of
complexes which undergo such changes are know, examples include
Cu(I).fwdarw.Cu(II) and Co(II).fwdarw.Co(III). In inorganic
chemistry other systems where a change in the coordination sphere
occurs on oxidation or reduction. Examples include species where
oxide ligands leave or enter the coordination sphere such as
MnO2.fwdarw.Mn2+, VO2+.fwdarw.VO2+.
[0067] Electronic leakage through the device can be controlled by
the choice of ion conductor, one such choice is use of ionic layers
in between the EC and the inorganic ion conductor or as a
replacement of the ion conductor. Examples of ionic layers being
poly(sodium 4 styrene sulfonate) and poly(lithium 4 styrene
sulfonate), polyamps, Nafion.TM. and ionomers (e.g., Surlyn.RTM.
from Dupont (Wilmington, Del.)). These materials are generally
described in U.S. Pat. No. 6,178,034. For EC devices where they are
activated to a bleached state, and it is desired that this state be
maintained for a limited time (few hours to a few days or even
weeks), reversible type EC devices are preferred. These devices can
be made to revert back to a more colored state by manipulating the
ion-conductor so that it has a finite electronic conductivity.
Alternatively, the two electrodes may also be joined by a high
resistance element in excess of about 100,000 ohms to tune the
desired amount of "open state" time. Typically, a thinner ion
conductor will have lower electronic resistance, thus more leakage
current. Also the microstructure of the ion conductor may be
manipulated, e.g., a given ion conductor when deposited in a more
dense form will have lower ionic conductivity if the other
parameters are held constant. Even with devices with no driving
potential, color may be lost because of oxidation, particularly for
those layers where coloration occurs in reduced state. Processing
conditions, e.g., sputtering or evaporation under high pressures
leads to higher porosity, use of elevated temperatures and use of
ion-assisted deposition reduces porosity. One may also use
materials which are colored in oxidized state, and these can be
bleached, but over time revert back to the colored state due to
oxygen diffusion in the product, an example of such EC material is
polyaniline. It is preferred to encapsulate the EC devices with
barrier layers so that permeation of oxygen and water is
significantly reduced. Further, these materials may also lend to
increased surface hardness. Several of these coatings are listed in
other section where hard coats are discussed. Preferred permeation
of oxygen or water through these layers at room temperature should
be less than 3.times.10.sup.-5 ml/cm.sup.2-day-atmosphere and less
than 8.times.10.sup.-5 g/cm.sup.2-day at 90% relative humidity
respectively. When EC layers, ion conductors and the
counterelectrodes are deposited by physical vapor deposition, it is
preferred that they have sufficiently open structures for ions to
go through and have low stresses. For example, EC coating porosity
is dependent on the ion to be transported. For example, the lithium
ion (Li.sup.+) has a size of 0.076 nm and O.sup.2- has a size of
0.145 nm (and O.sub.2 is about 0.17 nm). The channel size should
preferably be greater than about three times the ion diameter.
Typically low density or more porous structures are produced at
higher vapor pressures (keeping the other factors constant).
Pressures in the range of 10.sup.-3 to 5.times.10.sup.-5 torr are
generally preferred. The pressures are usually controlled by using
oxygen, nitrogen and/or argon. A method to deposit organic layers
or inorganic layers from liquid precursors is by printing of which
a preferred approach is by using ink-jet printing techniques, or
any other printing techniques including screen printing, offset and
gravure printing methods. Several companies offer capabilities of
ink jet printing on rigid substrates such as Litrex (Pleasanton,
Calif.), Dimatix (Santa Clara, Calif.) and Microfab Technologies
(Plano, Tex.). A combination of processes may be used to deposit
multilayer devices, i.e., some by printing and the others by PVD or
CVD. PVD is mainly used for metals and inorganic materials.
However, increasing use of printing including ink-jet printing is
being done for these materials. Typically nano-sized particles of
metals or inorganic particles is dispersed in a liquid medium and
used as ink. The particle sizes are generally less than 100 nm and
more in the range of 5 to 20 nm. As an example formation of such
particles in liquid phase are described in U.S. Pat. No. 6,322,901
and published US patent application 20050107478. Liquids comprising
nano-particles of inorganic transparent conductors (such as ITO and
IZO) and metals can be used for printing. For example Cabot
(Billerica, Mass.), ULVAC Technologies Inc (Methuen, Mass.) and
Harima (Japan) have nano-metal pastes (e.g., gold, silver, copper,
etc) for printing. Also, the RF antennas as described later may
also be printed (e.g., using ink jet printers) using these inks on
the same substrates as the EC devices.
[0068] Transparent conducting oxides may be deposited by a number
of methods. Preferred methods are those where these oxides may be
deposited at high rates to keep up with rates similar to metal
deposition in optical media to balance the throughput and minimize
the number of discs going through the process at any given time. It
is preferred that each layer of the conductive oxide or any other
layer in the conductive stack is deposited at about less than 15
seconds, and more preferably in less than 5 seconds, and two to
three seconds being most preferable. These are deposition times
only and not the period for evacuation through load-lock, etc.
Further, since the optical media substrate is made out of plastic
(generally polycarbonate), it is preferred that the substrate
temperature is at least 10 C below the glass transition temperature
of the plastic material. For polycarbonate media a preferred range
is below 130 C, and more preferably below 110 C, and most
preferably below 100 C. One preferred method is to use Pulsed DC
sputtering for high flux and simultaneous use of an auxiliary
oxygen plasma when using an alloy target of the component metals
(e.g., indium-tin or indium zinc, etc). The auxiliary plasma can be
generated by radio frequency (e.g., 13.56 MHz) or by the use of
microwaves. An example of pulsed DC power supply is Pinnacle Plus
available from Advanced Energy (Fort Collins, Colo.). A ceramic
target may also be used but one has to be careful about the thermal
loading. To get high flux in a small area where the coating is to
be deposited, hollow cathodes may be used rather than planar
cathodes. The material is sputtered through an inner diameter of
the target tube and the atoms exit from the end of this tube. This
type of system also has high coating efficiency as very little
material ends outside the desired coating zone. An important
parameter is to achieve a high flux of ions with energy closer to
about 20 eV/ion so that dense crystalline films are formed without
being disturbed too much from the kinetic energy of the arriving
ions.
[0069] For the access control, security, and theft protection as
envisioned here, the most desirable EC device could maintain its
colored and bleached state without having an appreciable potential
in either state. This means voltages in any state of coloration
should be lower than 0.5V and preferably less than 0.1V and most
preferably zero volts. Thus these devices will have low or no
internal driving potential which may lead to stable optical
characteristics when stored for long periods of time. It is best to
have devices exhibit this characteristic at all temperatures to
which the optical media is to be subjected to. However, in case the
devices change their optical state in a reasonable time at a
temperature which is below the destruction of the optical media so
that the protection of the media may be overcome, one can combine
these devices with passive thermochromic layers. The thermochromic
layer may be added to the EC device as a separate layer or a
thermochromic material may be mixed with one of the layers
comprising the EC device. In the latter case, one has to ensure
that the functionality of the EC device is still acceptable. The
function of the thermochromic layer will be to change its optical
state to a dark color so that the optical media cannot be accessed.
The temperature at which the thermochromic material transitions,
will have to be chosen so that the consumer in regular use is not
able to subject the optical media to this temperature. A preferred
transition temperature is around and above 85.degree. C. as one may
achieve this temperature on a hot day at a closed automobile
surface. A device with combined thermochromic and electrochromic
properties may also function or warn an end user of its illegal
acquisition or tampering. Further, the thermochromic material may
also be disabled by an irreversible chemical reaction when the
product is electrically activated by a legitimate application of
voltage. Similarly an electrochromic material may be combined with
a photochromic material. Where an unauthorized exposure to optical
radiation may result in the bleaching of the electrochromic
material, but the photochromic material would kick in to cause an
irreversible change in the optical properties to render the object
unusable or warn the user. One may combine electrochromic,
thermochromic and photochromic materials, all in one package. Thus,
one may use more than one type of change in a device to attain the
objective of security and theft deterrence.
[0070] FIG. 3 shows an EC device 35 with four layers. The metal
layer 36, EC layer 37, and the transparent conductor 39 are similar
materials as described above with reference to FIG. 2. The
ion-conductor 38 is used as a material that serves both as the
electrolyte and as a material that can absorb the ions from the EC
layer when powered. The layer 38 should not become electronically
conductive when oxidized or reduced. Since, this does not have an
electrode symmetry these can more readily form non-reversible
devices. These devices can also be driven at high voltages where
the ions react with layer 38 or even partially reduce the
transparent conductor. Examples of such layers are those comprising
silica, tantalum oxide, zirconium oxide, alumina and yittria. Since
these materials 38 are non-conductive they are not expected to have
any potential between the electrodes which will cause the ions to
move away from or move into the EC layer. In the bleached state the
ions react permanently, thus there is no driving force for the
devices to become colored when the device is left standing without
any applied potential. The EC layer may be reduced or oxidized in
any one of the ways to obtain the initial coloration as described
above. The CE layer may also be formed by using the organic or
inorganic ion-conducting materials with irreversible or reversible
redox materials.
[0071] One may also make the device in FIG. 3 in an inverted
sequence where counterelectrode layer 38 is first deposited on the
metal electrode 36 followed by the EC layer 37 and then the
transparent conductor 39. FIG. 4 shows another type of EC device 40
(thin film stack) which can be used for this purpose. In these
devices those EC materials 42 are preferred that do not become
conductive in either their colored or bleached states and thus do
not cause a short between the two electrodes. The metal 41 and the
transparent conductors 43 are similar as described above. Some of
the preferred EC materials are molybdenum oxide. To bleach (when a
potential is applied) the ions are irreversibly driven into the
metal layer or the transparent conductor. When ions are driven in
the transparent conductor, its conductivity may be reduced to a
point that the device in non-operational after this change. One may
add an insulating layer between the EC layer and one of the
electrodes to ensure that there is no electrical short in the
device this may be a thin layer of silica, zirconia, alumina,
yittria or tantala in a thickness range of less than 50 nm.
[0072] There are other types of EC materials that may also be used
where the metal layer itself participates in an EC reaction in
going from transparent to reflective or vice versa. U.S. Patent
Publication 20040021921 describes examples of these EC devices.
Antimony/bismuth and silver-antimony, copper-antimony and antimony
layers are preferred metals for this application where the metallic
(reflective) state goes to a transparent state when injected with
lithium. Further, the preferred range of antimony concentration
(atomic %) in these alloys is from about 40% to about 90%. One may
even use one ofthese compositions as one ofthe metal reflective
layers as a substitute for gold or aluminum in FIG. 1, and then
build an EC device on this layer.
[0073] These devices could be constructed as shown in FIG. 5 and
FIG. 6. For example, the device 45 may be constructed as in FIG. 5,
where the metal layer 51 is deposited on substrate 49 (readout
side, see FIG. 1, this metal layer is substituted for the data
layer (e.g., gold) in the EC device region or the entire disc).
Further this metal layer is one of those metal compositions that
changes from reflectance to the transparent state, then preferred
thickness of less than 50 nm and a more preferred thickness is less
than 30 nm. The electrolyte 48 is a lithium conductor such as
lithium niobate, lithium tantalte, lithium silicate, lithium
aluminosilicate, and lithium-phosphorous oxynitride (LIPON) in a
thickness of about 50 to 500 nm. The counterelectrode 47 is a
material that is transparent in its reduced state, example being
lithium doped cerium-titanium oxide, lithium doped titanium
vanadium, lithium aluminum fluoride doped with oxides such as
titanium oxide and molybdenum oxide may also be used in a thickness
range of about 100 to 500 nm. This is followed by a transparent
conductor layer 46 as described before. In these devices lithium is
inserted into the counterelectrode in several ways as described
above, such as co-deposition, chemical or electrochemical reduction
or depositing lithium as a separate layer which is then diffused in
the CE by heat, time or by applying a mild potential across the
electrodes. If this metal 51 is the same as the reflective layer in
FIG. 1, then this layer (in the active EC device region) is
lithiated by inserting the lithium ions so that it becomes
transparent. Thus in the transparent state (which will be closed
state for this device) the data is not read in Layer 0 (See FIG. 1)
as the reading laser beam passes through. When this layer is
subjected to a positive potential compared to the transparent
electrode then the lithium is driven out and it becomes reflective
to an extent that there is sufficient reflection from this layer to
read the data and also transmit enough laser power to be able to
read underlying layers.
[0074] One may also invert the layers for the device 55 as shown
below in FIG. 6 which also uses two metal layers. Metal 56 is the
gold layer, and metal 59 is the metal layer which changes from the
transparent to the reflective state deposited on the substrate, and
the description of the ion conductor 58 and the counterelectrode 57
remains the same as in FIG. 5. This type of an EC device may also
be put on the readout side of layer 1 (FIG. 1) starting with a
metal layer 59 such as gold in FIG. 6. All the other layers are
subsequently deposited and the EC metal layer 56 is deposited in
the EC active region so that it could change from transparent to
reflective. The counterelectrode 57 may contain the lithium
incorporated in one of the several ways discussed above. The device
when activated will cause the lithium to be injected into the
reflective layer 56 in the EC device area to be clear and be able
to read data. When Lithium is expelled it becomes reflective to the
point that either none of the reading laser intensity passes
through it and is unable to read data on any of the layers masked
by the EC layer, or changes to a reflective state which is so poor
that even the data on the readout side of Layer 0 is
unreadable.
[0075] Another example optical device uses at least two electrodes
with a polymer comprising electrolyte in between. Preferably these
are two of the metal layers used for data layers. If the data
layers are the two halves of the disc as shown in FIG. 1, the
bonding agent may serve as the electrolyte or will have
electrolytic components in the device region. The electrolyte may
comprise of an electrochromic material which may be anodic,
cathodic or may have both of these characteristics. Some of these
materials are described in US patent applications 2003/0234379,
2004/0257633 and in U.S. Pat. No. 6,853,472. In an example EC
device, a pH change is activated (acidic or basic) directly in the
electrolyte layer, causing one of the metal (i.e., electrode) layer
to gradually dissolve away making the data on that electrode
(layer) unusable. This dissolution may not be a physical
dissolution, but dissolution by creating a more soluble metal
species (or metal compound) formed as a result of the
electrochemical reaction. The formation of this chemical compound
may not be reversible. In solid devices the kinetics of forming
solid solutions may be so low, that the optical transition may be
observed only due to the formation of the new metal compound which
is more transparent. In general, the EC layer (metal in this
specific case) may be porous where the electrolyte penetrates these
pores in addition to forming a layer on top of the EC layer.
Porosity can allow for a faster interaction between the two layers.
The electrolyte although is a solid may have liquid or flexible
components which plasticizes the electrolyte matrix and allow
faster kinetics. One may further add reactive materials to the
electrolytes where this pH change causes them to change their
optical properties Further these property changes may also be aided
by moisture and/or oxygen diffusion into this layer from the
ambient atmosphere. As an example if the data layers are aluminum
and gold as the two electrodes forming the EC device, the aluminum
will corrode due to an oxidation reaction caused by pH change as
given by the following scheme: Al.fwdarw.Al+3+3e- and
Al+3+3OH--.fwdarw.Al(OH)3
[0076] The change to Aluminum hydroxide causes loss in reflection.
The oxidation reaction in the electrolyte in acidic medium (pH
lower than 7) leads to the following balancing reaction where
hydrogen will escape through the package
2H.sup.++2e.sup.-.fwdarw.H.sub.2 and in basic medium (pH higher
than 7) may lead to the following balancing reaction in the
electrolyte O.sub.2+2H.sub.2O+2e.sup.-.fwdarw.4OH.sup.- Other redox
additives may also be added to the electrolyte which will lead to
alternative balancing reactions. The electrolyte will also comprise
polymeric, monomeric or oligomeric components (e.g., acrylates and
methacrylates including urethane and epoxy acrylates). The layers
are typically put down from a liquid or a vapor precursor. Solid
layers are obtained by polymerization of the material in the layer
or evaporation of a solvent. The curing or polymerization may be
done by radiation (UV, microwave, etc.) and or heat. Depending on
the mechanism of cure appropriate initiators may also be added as
commonly known in the art. One may also use alternative polymeric
formulations as a matrix which are solidified upon cooling
(commonly called hot glue) or those materials which are processed
like hot glue to give immediate green strength for handling, but
can be further cured by UV or by mechanisms using room-temperature
vulcanizates (RTVs).
[0077] In the above description it was assumed that the EC is
located between the two halves of the DVD. Another highly preferred
location is outside of the DVD on the read-out side (see FIG. 1).
The thickness of the EC device (including conductive layers) is
preferred to be less than 10 microns, more preferably less than 5
microns and most preferable less than 2 microns. The EC device may
be covered by a clear hard coat which could be deposited by liquid
precursors or from vapor phase such as PVD and CVD and may be
assisted by plasma energy. The preferred thickness of the hard coat
is from 0.015 to 10 microns. Silicon, zirconium and aluminum
containing materials are preferred for the hard coating. Preferred
examples are silica, zirconia and alumina. The hard coats may also
be deposited by liquid processes (e.g., spin coating) that form
crosslinked polymers, typically acrylates and/or silicones. These
may be crosslinked using thermal or radiation (such as UV)
activation. These may also comprise of hard nano-particles
(typically 5 to 50 nm in size), some of these are metal oxides such
as silica, alumina and zirconia. An example is a spin coatable hard
coating from TDK (Japan) is DURABIS PRO such as PD-RE23CN. Hard
coats deposited by plasma processes from chemical vapors are also
available from Exatec (Wixom, Mich.) and Schott-HiCotec (Elmsford,
N.Y.). These hard coats also provide the barrier against moisture
and oxygen permeability.
Placement of the EO Device on a Disc and Integration with Other
Components:
[0078] FIG. 7 shows a DVD 70 with a central hole radius 71 for the
disc, the lead-in radius 72 and the radius for the beginning of the
program or data area 73. Typical dimensions for these in a
commercial DVD are 7.5, 22.6 and 24 mm, respectively. The burst
cutting area, clamping and the inner guard have diameters
respectively smaller than the lead-in area (not shown). Also shown
is an EC device 75 placed to cover part of the lead-in and the
program area. The EC device may be placed as such, or all within
the lead-in area or only in the program area. It may have a variety
of shapes or patterns as discussed later. The lead-in area is an
area proceeding the data area that typically holds important
information for data access, such as sector, menu, and control
information.
[0079] FIG. 8 shows the central part of the disc 70 (expanded from
FIG. 7 with more detailed features). In addition to the EC device
75, the central hole radius 71 and the start of the lead-in 72 and
the program area 73 radii, it also shows a microchip 76
electrically connected to the EC device via connection trace 79a
and also connected to an antenna 78 via connection trace 79b. The
microchip is located in the stacking ring area 77. The anti-theft
mechanism works in the following way. The EC device is in the
blocking or off-state when the optical media leaves the
manufacturing facility. Upon purchase of the optical media by the
end user, the chip, using the antenna communicates, via an RF or
any other wireless source, with a central network to authenticate
the transaction. Once the chip 76 receives an authenticating
signal, the chip applies a bleaching power to the EC device so that
it goes to an open state, or a state in which the laser beam in a
player is able to access the data on the disc.
[0080] The powering integrated circuit (IC) 76, or "chip" as it is
commonly known, is placed anywhere before the start of the lead-in
area. However, a convenient place for it to reside is the stacking
ring area 77. During the disc molding operation, a part of the
stacking ring is not molded to accommodate the chip. Typically the
chip may be about 5 to 100 microns in thickness (more likely 50 to
80 microns), so that it does not protrude beyond the stacking ring
thickness. Its width and length are preferably less than 2 mm by 2
mm or more preferably less than 1 mm by 1 mm. The antenna is placed
also within the inside part of the lead-in (before its start), and
preferably within the region inside of the stacking ring area so
that it is away from metal layers comprising the media, which
generally do not extend inside of the stacking ring. The antenna
may also be formed on a separate substrate such as a polymeric film
of polyester but electrically connected to the chip. The end-user
after purchasing and then opening the package may pull on the
antenna substrate, dislodge that and throw it away. There may be
convenient tear areas located so that it is easy to dislodge the
antenna or it may be affixed using tapes and adhesives which are
easy to tear. In one example, the antenna is removably adhered to
antenna contacts on the disc using a z-axis conduction tape as
described earlier.
[0081] A preferred chip is a flip chip geometry that has solder
bumps and may be assembled using conductive adhesive or solders to
electrical connections from the EC device or the antenna. The
connections from the EC device may be metal lines or transparent
conductor lines that culminate in pads for the chip. The conductive
adhesive or the solder may be cured/fused thermally, by radiation,
friction, laser or by ultrasonic processes. One may also assemble
the flip chips using Z-axis conductive adhesives as discussed
earlier, where solder bumps and underfill adhesives will not be
required.
[0082] The power to the IC may be supplied by a thin film battery
(not shown) which may be located near the IC or be built into the
IC. The power may also be supplied by coupling the antenna to an RF
power source. The IC is expected to deliver a voltage in the range
of 1 to 5V, preferably in the range of 1.5 to 3.5V. The IC is
preferably configured to deliver power for about less than 10 sec,
and more preferably for about less than 5 sec and most preferably
for about less than 2 sec. This time period is to allow the EC
device to change its state of optical characteristics to a
different optical state. The change in the optical properties of
the EC device may occur only while the power is applied or they may
continue for a long period (minutes to hours) after the activating
power has been applied. It is preferred that the device in the open
state (i.e., when the access to the data is allowed) pass or
reflect greater than 20% of the reading laser intensity as compared
to a data region where there is no EC device. A more preferred
number is greater than 60% and most preferred is greater than 85%.
A higher transmission will allow the laser to scan flawlessly from
the EC region to the rest of the DVD. Similarly, the closed state
of the device (where it is unable to access data) should transmit
or reflect less than 20% of the laser intensity compared to a data
region where EC device is not present. More preferably this number
should be less than 20% and most preferably less than 5%. These
numbers are measured using the wavelengths of the reading laser
which is dependent on the type of media.
[0083] FIG. 9 shows an expanded view of the arced EC device. In
FIG. 9, 80 is the burst cutting, lead-in and the data area, and 90
is the stacking ring, clamping and the inner guard area. Deposition
of various layers and connectivity to a powering IC are
demonstrated using a four-layer device as shown in FIG. 3. The EC
device is constructed by depositing gold in area 80 and also some
parts of 90 as shown by the shaded area 101 and 102. There is no
electrical continuity between area 101 and 102. This can be done
through a mask or coating the entire disk with gold and then using
photolithography to remove gold from selected areas. This gold
layer may be the metallic layer L0 in FIG. 1 if the EC device is
being deposited inside the DVD halves and using gold as one of the
EC electrodes. This may also be a transparent conductor which may
be deposited inside or on the outside surface of the device. The EC
device is shown as 60, of which the active electrochromic area is
shown as 105. Next EC material 105 is deposited, which may be
tungsten oxide by sputtering. It will be appreciated that other EC
materials and disposition process may be used. This layer may be
colored by co-depositing lithium or depositing lithium as an
additional layer which is later intercalated. One way to deposit
lithium is by using a lithium-aluminum alloy target, where the
sputtering/or evaporation conditions selectively remove lithium.
Alternatively using a solution of strong reducing agent such as
butyl-lithium may chemically reduce tungsten oxide. This layer is
deposited through a mask in a selected area. This is then covered
using a larger mask with layer 103 which is an electrolyte and
counterelectrode shown as 103. Finally a layer of ITO 104
(transparent conductor) is deposited using a smaller mask as
compared to layer 103. Care should be taken that the TC does not
touch the gold layer in any region other than in area 101 as shown
by 106. As illustrated, bump 110 and bump 111 are the contact
points where the IC chip is connected to the device using a
conductive adhesive, bump connections, or some other means. The
figure also shows an RF antenna 120, which is connected to the IC
chip (not shown) via the connection pads 121 and 122.
[0084] FIG. 10 shows a masking system 100 for forming an EC device
with connections to be able to connect with other components. This
device is deposited on the outside surface comprising of two
transparent conductor electrodes made out of ITO. This deposition
is also conducted using PVD for illustrative purposes. Layer 1 made
of aluminum fluoride is deposited through a rectangular Mask 1.
This acts as adhesion promoter between the polycarbonate surface of
DVD and that of the next ITO layer. The first ITO layer is
deposited through Mask 2. This is followed by nickel oxide
deposited through Mask 3 (the shape of the active EC area). Through
the same mask lithium is evaporated to dope nickel oxide. Mask 4 is
larger than Mask 3 and it is used to deposit the ion conductor
LiAlF4. This ensures that there will be no short between the bottom
layers and the layers to be deposited on top of it. Through Mask 5,
which may be the same as Mask 3, tungsten oxide is deposited.
Finally through Mask 6 the second ITO layer is deposited, thus
completing the device. As shown in the composite 101 in FIG. 10,
the two ITO layers are separated at the bottom which may be
connected to the other components. Mask 3 and Mask 5 are not shown
in this composite as they are hidden behind other layers. It will
be appreciated that other materials may be substituted as
previously described.
[0085] An alternative connection scheme 110 is shown in FIG. 11
where the two ITO layers 111 and 112 are on top of each other and
an insulating layer 113 between them keeps these from shorting. The
insulating layer may also be the ion conductor of the EC device. In
this figure the two ITO layers are shown with slight stagger only
to be able to illustrate the point, however, they can completely
overlap one another, and only come out as separate pads at the
bottom shown by 111a and 112a. The areas of these protrusions are
just sufficient for these to be bonded to the chip. In this
geometry it is difficult to access the two ITO paths from outside
through probes, to bleach the EC device.
[0086] When the EC device and the chip and the antenna are located
between the two halves of the DVD to accommodate the thickness of
the IC, the one half may be molded with an indentation and then
properly oriented and placed on the other half for bonding.
Alternatively, one may have an indentation on the same half where
the IC is placed, and the coatings operation of the metal layer and
the TC is done so that it extends into the indentation. The pads on
the IC may be bonded using conductive adhesives or using low
melting point solders such as those based on indium. The conductive
adhesives may be rigid such as based on epoxies or be flexible
using silicone matrices. A variety of these are available from many
sources, and one source being Emerson and Cummings (Billerica,
Mass.). The same IC may have additional bonding points to contact
the RF antenna and associated circuitry if used. In another
alternative the IC may be embedded in the same half which has the
EC device with only the contact points exposed so that the layers
when deposited come in contact with these exposed contacts. The IC
may be embedded during the molding operation. Further using
injection molding technologies such as those used for molded
interconnected devices (MID) and three dimensional MID (3D-MID) one
may embed ICs and antennas which are connected and also allow
tracks on the substrate to connect to the EC device electrodes as
they are formed.
[0087] One may also form a complete EC device using thin metal
layers or transparent conductors on polymeric film, preferably of a
material that is used to manufacture the disc, some of the films
which may be used are polycarbonate, acrylic, polyester,
polyethyleneterephthalate or the cyclic polyolefin. These films
should preferably be heat stabilized. The polymeric film thickness
is usually less than 150 microns on which the multilayer device is
deposited. Optionally, the IC and the antenna can also be assembled
on the same film. This is then placed between the two discs (the
bonding area, see FIG. 1) but roughly located in a region as shown
in FIGS. 8 and 9. To accommodate the thickness of the film, antenna
and the IC, one may make provision of this during the molding or
stamping operation. One may only make the provision to accommodate
the IC and antenna thickness if the film thickness will be
accommodated within the bonding layer. Alternatively, the film with
the device and all the other components is placed on the outside
surface of the bonded disk. One may use molded interconnect device
(MID) technologies to integrate all or part of these components,
form electrical connections with each other and be assembled on to
the disks (e.g. see MIDs Make a Comeback
http://www.plasticstechnology.com/articles/200506fal.html, by
Joseph A. Grande Plastics Technology, June, 2005). Antennas and EC
films and other components may also be formed on a substrate and
transferred to the injection molded discs using a technology called
In-mold decoration (Nissha, Japan) or see PCT application WO
2004085130. When EC devices along with electronics and antenna are
placed in a disc, it may desirable to ensure that the disc is
dynamically balanced as the disc is required to spin at high speeds
in the playback equipment. On technique for doing so is to add
counterweights, remove material (e.g. polycarbonate) and replace it
with lighter materials or leave a void.
EXAMPLES OF EC MATERIALS AND DEVICES
Example 1
EC device with MoO3+AlF3 Counterelectrode Processed by PVD
[0088] A set of four EC devices were fabricated on a conductive tin
oxide coated glass by depositing coatings using physical vapor
deposition (PVD). This was a five layer device similar to the one
shown in FIG. 2 comprising of an EC layer, ion conductor and a
counterelectrode sandwiched between two conductors. The devices
were appropriately masked from each other to generate four
independent devices in a size of about 1.5 cm.times.1.5 cm. The
first layer was 500 nm tungsten oxide evaporated by an electron
beam. Then 60 nm thick lithium metal was evaporated to dope and
reduce tungsten oxide to its colored bronze (corresponding to about
24 mC/sq.cm of charge). An ion conductor comprising aluminum
fluoride and lithium was deposited next in a thickness of 500 nm.
This was followed by a counter electrode comprising about equal
proportions of molybdenum oxide and aluminum fluoride in a
thickness of 100 nm and the top conductor which was 9.5 nm thick
gold layer. The device as fabricated was colored and when 1.5V was
applied (gold electrode being negative) the device bleached. The
colored transmission at 650 nm was 4.4% and bleached transmission
was 20.5%. In a separate experiment the transmission of a 9.5 nm
gold coating on glass was measured to be 42% at 650 nm.
Example 2
EC Device with NiO Counterelectrode Processed by PVD
[0089] Another set of devices was fabricated as in Example 1.
however, in this case the counterelectrode was 120 nm thick nickel
oxide. At 650 nm, this device in colored state was 2.6%
transmitting and in the bleached state the transmission was 15.1%.
The colored state transmission at 405 nm was 6.9% and 22.6% when
bleached.
Example 3
Electrochromic Polyaniline (PA) Coating
[0090] PA was deposited on ITO coated glass. The coating was
deposited from a solution comprising formic acid and ascorbic acid.
The coated substrate was heated to 70.degree. C. for 15 minutes to
remove the volatile products and solidify the coating. The 300 nm
thick coatings were colorless as produced and were electrochromic
as shown in FIG. 12 and the table below. FIG. 12 has a graph 120
that shows a % Transmission 121 versus wavelength 122 for the ITO
substrate 123, the reduced PA 124, and the oxidized PA 125.
TABLE-US-00001 % Transmission at 650 nm 550 nm 405 nm Polyaniline
Bleached 71.6 75.8 52.8 Colored 28.7 50.0 18.2 ITO substrate only
84.0 87.7 73.4
Example 4
Transparent Conductor Coatings for the EC Devices
[0091] Two type of coatings, Indium tin oxide (with about 0.1 as
tin to indium atomic ratio) and indium-zinc oxide (with about 0.3
zinc to indium ratio). These coatings were deposited on glass
without heating. These coatings were deposited by sputter coating
process in a thickness of about 100 nm. The resistivity of ITO was
45 ohms/square and of the IZO 60 ohms/square. Their optical
transmission spectra is shown in FIG. 13. FIG. 13 has a graph 130
that shows a % Transmission 131 versus wavelength 132. It appears
that for devices using light sources at 405 nm, IZO 133 will be
preferred over ITO 134 from an optical perspective. In FIG. 12, the
transmission of ITO was high at 405 nm indicating that the
transmission of this layer is also morphology dependent which for a
given composition can be controlled by the processing
parameters.
Example 5
Solution Deposited Tungsten Oxide Coating Reduced with Protons
[0092] A tungsten oxide coating on ITO (12.OMEGA./sq) was prepared
from a precursor solution. The precursor solution was prepared from
3 grams of peroxotungstic ester (PTE) dissolved in 30 mls of
ethanol. The solution was spin coated at 1000 rpm onto ITO and
cured under humid conditions to 135.degree. C. The WO3 coating had
a thickness of 250 nm. This coating was chemically reduced to a
colored state by subjecting this to dilute sulfuric acid and indium
metal.
Example 6
Ion Conducting Layer Cured by Radical Polymerization Using UV
Light
[0093] A UV curable solid electrolyte was prepared by mixing 3.75 g
of poly(propylene glycol) diacrylate with 1.25 g of poly(propylene
glycol) acrylate and 0.2 g of the UV initiator Irgacure 500
(supplied by Ciba Speciality Chemicals Corp. White plains, N.Y.).
To enhance the ionic conductivity of the mixture 0.77 g of
1-Butyl-1-methylpyrrolyidium
1,1,1-trifluoro-N-[(trifluoromethyl)sulfonyl]-methanesulfonamide
ionic liquid and 0.16 g of lithium trifluoromethanesulfonate. A
thin coating of the mixture was cured to a solid film by exposing
this for 5 seconds in a Xenon strobe light curing system (Model 550
from Electro-lite Corporation (Danbury, Conn.)).
Example 7
Ion Conducting/Electrochromic Layer Cured by Cationic
Polymerization Using UV Light
[0094] A cationically cured cathodic layer was made using the
following: [0095] 4 g of epoxy resin CyracureUVR-6105 (Dow
chemical, Midland, Mich.) [0096] 0.717 g polypropylene polyol
Voranol PT700 (Dow Chemical, Midland, Mich.) [0097] 0.189 g
photoinitiator UV1 6976 (Dow Chemical, Midland, Mich.) [0098] 0.024
g silicone surfactant Silwet L-7604 (GE silicones, Scnechtady,
N.Y.) [0099] 1.488 g 1-Butyl-1-methylpyrrolyidium
1,1,1-trifluoro-N-[(trifluoromethyl)sulfonyl]-methanesulfonamide
ionic liquid (or salt) [0100] 0.493 g diethyl viologen
1,1,1-trifluoro-N-[(trifluoromethyl)sulfonyl]-methanesulfonamide as
the EC material This formulation was spin coated at 2000 rpm and
cured under the Lesco Rocket Cure system (Torrance, Calif.) for
approximately 60 seconds forming a 9 microns thick film. When this
formulation was diluted with methanol much thinner coatings were
prepared. These coatings were cured after methanol evaporated. When
viologen salt was left out from the formulation, ion conducting
coatings were obtained.
Example 8
Ion Conducting Layer Containing REDOX Species Cured by Radical
Polymerization Using UV Light
[0101] A UV curable solid electrolyte was prepared by mixing 3.75 g
of poly(propylene glycol) diacrylate (Mol wt. 540) with 1.25 g of
poly(propylene glycol) acrylate (Mol wt 475) and 0.5 g of
dipentaerythriol pentaacrylate ester and 1.0 g of amine modified
acrylate oligomer, acrylic ester. 0.4 g of the UV initiator
Irgacure was added. 0.06 g of glycidoxypropyltriethoxysilane was
added as an adhesion promoter. To enhance the ionic conductivity of
the mixture 0.246 g of 1-Butyl-1-methylpyrrolyidium
1,1,1-trifluoro-N-[(trifluoromethyl)sulfonyl]-methanesulfonamide
salt and 0.046 g of lithium trifluoromethanesulfonate salt were
added. The redox species ferrocene was added in a concentration of
0.282 g. This mixture was spin coated on glass and cured for 5
seconds in a Xenon strobe light curing system (Model 550 from
Electro-lite Corporation (Danbury, Conn.)). The film thickness was
9 .mu.m
Example 9
Electrochromic Device with Tungsten Oxide UV Cured Layers and Gold
Electrode
[0102] A thin layer of the ion conducting material describe in
Example 8 above was spin coated at 1000 rpm onto tungsten oxide as
described in Example 5, but without the reduction step. The ion
conducting layer was cured under UV to give a solid layer 9 microns
thick. On top of this layer was deposited 50 nm of gold by a
sputtering process to complete the stack and form the top
electrode. The cell had an initial reflectivity of 68% at 650 nm
and when colored by applying 3.5 volts had a reflectivity of
31%.
Example 10
Laminated Solid State Lithium Electrochromic Device
[0103] A solid state electrochromic device was constructed using a
tungsten oxide coating as described in Example 5 above except the
WO3 was cured at 250.degree. C. and the coating was reduced in a
three electrode configuration using 0.1M lithium
trifluoromethanesulfonate and 0.05M ferrocene in propylene
carbonate as the electrolyte. The reference electrode was a silver
wire. The reduced WO3 on ITO was laminated with another ITO coated
substrate through use of the ion conducting layer as described in
Example 6. This bonding layer was cured under UV and had a
thickness of around 30 .mu.m. The initial transmission of the cell
at 650 nm was 55% and when bleached at 3.5 Volts at room
temperature its transmission increased to 80%. This cell in the
bleached state along with another cell in the colored state (50% T
at 650 nm) were stored at room temperature for three days without
applying any electrical power. Both the cells did not show any
optical change. To see if elevated temperature storage would
accelerate a change in optical properties, both of these cells were
then subjected to 85.degree. C. for six days without power
application. Again no change in optical properties was observed
with no change in its optical transmission. This shows that in both
cases the optical states were maintained without applying any
electrical power.
Example 11
Laminated Solid State Proton Electrochromic Device
[0104] An electrochromic device was prepared as described in
example 10 above except that the WO3 layer was cured at 135.degree.
C. and reduced with protons using dilute sulfuric acid and indium
metal. The cell at 650 nm had a transmission of 3% and when
bleached at 4.0 volts had a transmission of 78%. This cell was
placed in the bleach state at 85.degree. C. for six days with no
change in transmission or physical appearance of the cell.
Example 12
Thin Film EC Device with UV Cured Electrolyte
[0105] An electrochromic device 140 was made by depositing thin
layers as shown in FIG. 14. The substrate used was glass 141, but
it could have been a DVD substrate such as polycarbonate. ITO layer
142 was 150 nm thick with a conductivity of 15 ohms/square. This
was followed by 250 nm tungsten oxide layer 143 which was deposited
and reduced by the method described in example 5. The ion conductor
layer 144 was formed by using a standard DVD bonding adhesive
Dicure Clear EX 7000 (from Dinippon Ink and chemicals, Japan) and
mixing this with 01M
1-Butyl-1-methylpyrrolyidium1,1,1-trifluoro-N-[(trifluoromethyl)sulfonyl]-
-methanesulfonamide (ionic liquid or salt) and 0.1M 15-crown-5
ether. The thickness of this layer was 2 .mu.m, followed by a top
gold electrode 145 in a thickness of 50 nm. Gold could also have
been replaced by a transparent conductor in about the same
thickness. This device was colored blue as observed in reflection
through the clear substrate. When a potential of 3V was applied to
the device (Gold being negative compared to the ITO) the device
bleached.
Example 13
EC Device on a DVD
[0106] FIG. 15 shows a DVD 150 with an EC device 151 in the shape
of a truncated diamond. This EC device 151 was made by physical
vapor deposition of several layers as shown below on the outside
surface of a pre-bonded DVD. [0107] Disk
(Polycarbonate)/ITO(1)/LiNiO/LiALF4/WO3/ITO(2) [0108] ITO(1): 100
nm [0109] NiO: 100 nm [0110] Li: 10 mC/cm2 [0111] LiAlF4: 750 nm
[0112] WO3: 300 nm [0113] ITO (2): 50 nm The device could be
colored or bleached by applying 1V. For coloration ITO(2) was
negative, and the polarity was reversed for bleaching. In the
colored state the DVD did not play on a computer DVD player. In the
bleached state the DVD played normally.
Example 14
EC Device with High Stability in Colored and Bleached State
[0114] A device was made using two pieces of glass with ITO
coatings. On one of these a polyaniline coating in a thickness of
700 nm was deposited on a spin coater at 200 rpm as described in
Example 3. This was assembled in a cell with a liquid electrolyte
comprising of propylene carbonate to the ionic liquid in a ratio of
4:1 and 0.25 molar hydroquinone. The ionic liquid was
1-Butyl-1-methylpyrrolyidium
1,1,1-trifluoro-N-[(trifluoromethyl)sulfonyl]-methanesulfonamide
and the other side being ITO on coated glass. In principle the cell
resembled FIG. 3 where the EC layer was polyaniline. The
electrolyte thickness was about 70 microns. The transmission of the
cell at 650 nm was 2%. The two transparent electrodes of the cell
were shorted. There was no change in the cell optical properties
for several days. The potential between the two electrodes was
negligible. When a potential of 2V was applied with polyaniline
side of the cell being negative, the cell transmission changed to
about 30% in 7.5s. After bleaching the cell was shorted again. The
transmission of the cell relaxed by a couple of percent to about
28% and then it did not change for several days. The potential
between the two electrodes was not measurable (close to 0V) in this
state.
Example 15
Formation of Solid Hydroquinone Materials and Coatings
[0115] A solid hydroquinone polymer was synthesized using an
acetate (Ac) as shown below using ring opening metathesis
polymerization (ROMP) ##STR1## Another solid electrolyte containing
hydroquinone was prepared by reacting 3.5 wt %
poly(diallydimethylammonium chloride) with 0.875 wt % hydroquinone
in 50:50 water/ethanol mixture. The solution was spin coated onto
ITO at 1000 rpm and cured at 80.degree. C. to give a transparent
colorless coating. The coating was 562 nm thick and contained 25 wt
% hydroquinone based on the solid polymer content. The coatings
were water clear. For this coating to be incorporated in an EC
device, a polyaniline coating was over-coated with the hydroquinone
comprising coating and stored for ninety minutes at 80.degree. C.
with no change in its optical transmission at 650 nm. Solid
hydroquinone or coatings of other organic materials may also be
formed by thermal evaporation of these materials in vacuum.
Example 16
Polyaniline Coatings Inside the DVD and Playability
[0116] Several DVDs were coated with polyaniline solutions (see
example 3) by spraying through a mask to create a pattern as shown
in FIG. 15. These patterns were created before the two halves of
the DVD were bonded (see FIG. 1). The patterns were put directly on
the metallic layer of the L0. In one case the transmission of the
coating was 1% and in another case the coating was bleached with a
transmission of 47% at 650 nm. The transmission measurements are
reported by putting similar coatings on glass and measuring the
transmission of the coated glass. The two halves i.e., coated L0
and non-coated L1 were bonded by a UV curing glue from DiNippon Ink
(Japan) used for this purpose. Glue thickness was about 40 microns.
The one with the colored pattern did not play on any of the
following players and the bleached one played on all of these.
TABLE-US-00002 Panasonic (Japan), Sony (Japan), Model Model
CyberHome (Fremont, CA), DVDS29S DVPNS50PS Model CH-DVD500
Example 17
Polyaniline Doped with Hydroquinone (HQ)
[0117] A polyaniline coating was deposited by spin coating a
solution (0.6 g of polyaniline (emeraldine base, 50,000 mol wt) in
20 ml of 88% formic acid) on an ITO coated glass substrate. The
coating is dried in an air circulated oven at 80 C. The color of
the coating as deposited is deep green and after the drying process
it is deep blue. The coating thickness was about 300 nm. Doping
with hydroquinone was achieved by soaking the polyaniline coating
in a solution of 0.25M hydroquinone in 80 vol % propylene carbonate
and 20 vol % ionic liquid at 80.degree. C. for 5 minutes and then
washed with ethanol. After doping, the polyaniline changed from
deep blue to pale yellow. The coating had an active cyclic
voltametry (CV) response and could be colored and bleached. CV was
conducted in 0.1M lithium triflate solution in acetonitrile while
using a stainless steel counter electrode and silver as
pseudo-reference electrode. At a scan rate of 20 mV/s, the
electrode was colored at -0.56V versus silver wire and the optical
modulation was recorded as shown below. TABLE-US-00003 Modulation
Range of Hydroquinone Doped Polyaniline Polyaniline Doped with 405
nm 650 nm 780 nm Hydroquinone % Transmission Reduced 54 66 63
Oxidized 3 7 1
[0118] The modulation of hydroquinone doped polyaniline was
surprisingly high at 405 nm. Thus this was deemed as a suitable
material at all the three wavelengths of interest. Further, this
material had good thermal stability in both (colored and bleached
states) as shown in the next table where the transmission change
was recorded for both states by subjecting them to an air
circulated oven at 80 C. No change in colored state at 650 and 405
nm was observed for a period of two hours. In the bleached state
the transmission at 650 nm decreased from about 66 to about 40% and
at 405 nm this changed from 54 to 50%. It appeared that the change
at the end of two hours was leveling off. Derivatives of
hydroquinone and their mixtures with hydroquinone were also found
suitable to give large range at both 405 and 650 nm. For example in
a separate experiment the following results were obtained.
TABLE-US-00004 405 nm (% T) 650 nm (% T) Dopant Reduced Oxidized
.DELTA.(405 nm) Reduced Oxidized .DELTA.(650 nm) Hydroquinone 42 7
35 57 15 42 Trimethylhydroquinone 49 27 22 65 58 7 Hydroquinone/ 45
14 31 62 51 11 Trimethylhydroquinone
Example 18
Solid EC Cell with Polyaniline Doped with HQ and with UV Curable
Electrolyte Layer
[0119] A doped HQ containing polyaniline was prepared as in Example
17 on an ITO coated glass substrate and then incorporated in the
device. Polyaniline was bleached when incorporated in the device.
ITO conductivity was about 15 ohms/square. The substrate size was
about 2cm.times.2cm and the area coated with polyaniline was about
0.75 sq cm. A layer of UV curable electrolyte with the following
composition was coated on top of doped polyaniline: [0120] 7.5 g
Poly(propylene glycol) diacrylate (mol. wt. 475) [0121] 2.5 g
Poly(propylene glycol) acrylate (mol. wt. 540) [0122] 0.5 g
Pentacrylate (SR399LV from Sartomer, Exton, Pa.) [0123] 0.05 g
Amine(CN371 from Sartomer, Exton, Pa.) [0124] 0.46 g Irgacure 500
(from Ciba Specialty Chemicals, White Plains, N.Y.) [0125] 2.4 ml
Propylene carbonate [0126] 1.0 ml 1-Butyl-1-methylpyrrolyidium
1,1,1-trifluoro-N-[(trifluoromethyl)sulfonyl]-methanesulfonamide
[0127] 0.1 g Lithium trifluoromethanesulfonate (0.05M)
[0128] After coating with electrolyte another ITO coated glass of
similar size, with a slight offset was lowered on top of the
electrolyte with ITO touching this layer. The sandwich was then
subjected to UV radiation for cure. The thickness of the
electrolyte layer was about 1.5 microns. When a voltage of 2.75V
was applied with polyaniline electrode being positive, the cell
colored. The cell bleached when a reverse potential of 2.75V was
applied. This is shown in FIG. 16 at 405 and 650 nm. The cell
potential in colored and bleached state was 0 Volts. The cell was
stored in colored state and a similar cell was stored in the
bleached state at 80 C. Both of these were shorted when stored in
either of the states. Their stability was high as seen from the
change in transmission with time in FIG. 17.
Example 19
Additives to PANI to Improve its Adhesion to Other Coatings
[0129] For devices to work properly it is important that all layers
must have good interface adhesion for proper transport of ions and
electrons. We found that to improve the adhesion of polyanilne with
other layers, particularly ion conducting layers deposited over it,
that it is preferable to modify the polyaniline coating solution by
adding ion-conducting material to it. For example addition of
polymers with acid containing moieties, such as polyacrylic acid
(PAA), Nafion.RTM.) (Dupont, Wilmington, Del.), or polystyrene
sulfonic acid was useful. The ion-conducting material coatings on
top of modified polyaniline showed superior wetting during the
coating operation. Further, the polymer added to polyaniline may be
the same as the ion conducting layer or be a different one. The
concentration of modifying polymer was preferably 50% of
polyaniline by weight. A more preferred concentration was 10% or
less.
Example 20
Devices with Polyaniline and Thiophene as Reductant
[0130] To make irreversible devices with no potential in the
colored and the bleached states it was decided to couple
non-reversible chemical reactions which were induced
electrochemically. In these devices the expected reaction upon the
application of bleach potential was electrochemical bleaching of
the EC layer while a non-reversible polymerization was initiated of
the thiophene. The devices were constructed with polyaniline (with
10% polyacrylic acid (molecular weight 2000) by weight ). The
coatings were deposited on ITO coated glass by spin coating from
88% formic acid solutions. The thiophene was dissolved in a
polyelectrolyte (PSS (polystyrene sulfonic acid), Nafion.TM. or
PSSNa (polystyrene sulfonic acid; sodium salt)). The nafion
solution was prepared in lower alcohols, the PSS and PSSNa
solutions were prepared in water:ethanol 50:50. This was coated on
a second ITO coated substrate, and these were assembled into a
device by bringing the two coated substrates together and
sandwiching an electrolyte. Initial experiments were carried out
using liquid electrolytes which comprised of 0.1 molar lithium
triflate in propylene carbonate. FIG. 18 shows that a cell made in
this fashion with thiophene acetic acid had stable colored and
bleached state when shorted. A similar cell was made where
polyaniline was substituted with poly(2-methoxyanilne) and
thiophene acetic acid was substituted with 2-nitrothiophene. This
cell also showed good stability in both states.
Example 21
Devices with Polyaniline and Metal Salts as Reducing Agents
[0131] Devices are constructed with polyaniline coatings with
similar compositions and process as in Example 19. The reductants
are metal salts which are dissolved in a polyelectrolyte (PSS
(polystyrene sulfonic acid), Nafion.TM. or PSSNa (polystyrene
sulfonic acid; sodium salt)) in an aqueous solution comprising
ethanol and water and coated on top of the polyaniline layer. To
make a coating solution, 1 g of vanadyl sulfate was added to 2 g of
polyacrylic acid and 8 ml of water. Then 0. 1 ml of this was added
to 0.5 ml ethanol and 0.5 ml of polystyrenesulfonic acid (18 wt %
in water) to make the coating solution. The device was constructed
where polyaniline was 300 nm thick, electrolyte was 2.9 microns
thick and the top electrode was gold in a thickness of 60 nm. The
device had an initial reflection of 8% which changed to about 27%
when a potential of 2.8V (polyaniline being negative) was applied.
This device exhibited stable states when shorted in bleached and
color mode. The device had no measurable potential across the
terminals in either of the optical states. Another device was
constructed where cobalt chloride was used instead of vanadyl
sulfate. This also showed stable optical characteristics in both
states and the device changed from about 7% reflectivity to 18%
reflectivity when bleached at 2.8V.
Example 22
Playability of Disks Coated with Polyaniline
[0132] Several polyaniline coatings were deposited in the pattern
and position as shown in FIG. 13 on the read side of as many DVD9s
by spray coating through a stencil. The transmittance of these
coatings when deposited on glass was 14, 35, 57, and 62 and 79% at
650 nm. These were evaluated for playability for on a personal DVD
player (Emprex Model PD 7001, Emprex Technologies, Fremont,
Calif.). The disks with coatings having a transmission of 14 and
35% did not play, whereas the others did.
Example 23
Playability of Disks Coated with Open and Closed EC Shutters
[0133] Two DVD-9 were coated with passive truncated diamond-shaped
shutters, one in the open state and one in the closed state. The
device stacks consisted of physical vapor deposited layers of
ITO/WO3(Li)/Li/AlF4/ITO as shown by the photograph in FIG. 19. The
radial extend of the truncated diamond covered a radius from
approximately 22.6 mm through approximately 28.5 mm, with a maximum
tangential extend of about 12 mm. In the closed shutter shown in
FIG. 19, the WO3 was lithiated with sufficient charge to bleach the
shutter for open state simulation. FIG. 20 shows the digital error
rate (measured as errors per 8 error correction code (ECC) blocks
of the channel code for a DVD) for Layer 1 for the closed shutter
and the open shutter measure by a DVD CATS Tester manufactured by
Audio Development (Malmo, Sweden). As a reference the error rate
from a disc from the same batch as the open shutter is also shown.
Even though, for this particular open shutter there exist some
elevated errors in the focus and track servo signals, the resultant
increase in digital error is still small and well within the
specification limits for DVD of a maximum 280 errors per 8 ECC
blocks. The error rate for the closed shutter, however, sharply
increases as the disc is played back from the outer diameter
towards the inner diameter on the Layer 1 information layer of the
opposite track path disc. Playback was ceased at approximately a
radius of 26.2 mm before reaching the maximum tangential extent of
the closed shutter.
Shapes Geometry and Location of EO Device
[0134] Due to differences in their optical properties, the
transition from an area of the disc without an EC device to an area
with an EC device may introduce variations that affect the ability
of a reading or writing device or player to read from, or write to
impacted areas of the disc. In cases where the EC device covers the
entire disc and extends beyond the data structures, this "edge"
does not affect the ability of the reading or writing device or
player to read from, or write to the disc. It is often desirable,
however, for the EC device to be smaller than the entire surface
area of the disc. A smaller device lowers manufacturing costs (e.g.
lower material costs, higher yields, and shorter production times),
requires less power and switches states faster. Since it does not
completely extend beyond the data structures, the edge of a smaller
EC device may affect the ability of a reading device to read from,
or writing device to write to the disc.
[0135] The EC device may have different geometries depending on the
technology and placement region of data and reference files which
need to be enabled or disabled by a manufacturer, vendor, user,
etc. The EC device may be placed in a shape of an arc or another
shape. The arc may also extend around the entire circumference or
there may be more than one arc placed around the circumference or
several radial patches. Each patch, may, for instance, be tuned for
a particular wavelength of the readout beam, such as 650 nm and 405
nm for DVD, to prevent reading of the disc in the closed shutters
state at both wavelengths. One may even cover the entire lead-in
area, or the entire program area or both of these. The EC device
may also be patterned in shapes such as stripes, cross lines, etc.
The pattern may be in a form of diffraction grating which when
colored will form a pattern akin to zones of different optical
densities and diffract the laser beam. The pattern may be such that
it covers selective data sectors or parts thereof so that critical
information needed for the disc to function may be optionally
disabled. One may also put a pattern such that the servo mechanism
(e.g. for tracking or focusing onto an information track) loses
lock subsequently rendering data retrieval impossible from a
particular area of the information layer according to a required
protocol. A patterned approach allows one to decrease the active
area of the EC device. For an arc shape EC device intended for a
DVD its active area should have a preferred arc length of about or
greater than 7 mm, and its width be about greater than 0.5 mm. This
may (active area) be a square in a size greater than about 7 mm x7
mm, or a rectangle with the tangential dimension being greater than
about 7 mm and the other (radial dimension) preferably being
greater than the tangential dimension. Smaller EC devices will
require less power to switch, as the power requirements will
typically be proportional to the active area. A preferred limit for
the amount of power to switch the EC device is below 25 mW, and
preferably below 5 mW. This is because the power is derived from
the antenna when it is activated, which is limited. Thus preferred
active area of EC device is less then 5 square cm, and preferably
less than 2 square cm and most preferably less than 0.5 square cm.
The switching time is also limited at check-out when the chip is
activated. Thus the power application time for bleaching is less
than 10 seconds, and preferably less than 5 seconds and most
preferably less than 2 seconds. The EC device may fully bleach in
this period, or may continue to self-bleach after the power
application has stopped over the next several minutes to hours.
[0136] FIG. 21 shows another exemplary pattern for the EC device.
The EC active area is shown as a diamond in FIGS. 21a-c. This could
replace area 75 as shown in FIGS. 7 or FIG. 8. The whole area
within the diamond shape may be an EC device or it may be patterned
as shown FIG. 21b and 21c where only the darker areas are EC active
and the areas between them are transparent and not switchable. As
these will be powered with electronics with only a limited amount
of power, it is best to minimize the EC active area. Preferably,
the charge consumption for switching should be kept lower than IC,
and more preferably lower than 100 mC and most preferably below 10
mC. Assuming that a typical EC device when powered between 1 to 5V
may consume about 10 to 30 mC of charge per cm.sup.2, it is best to
have the active device area lower than 5 cm.sup.2, and preferably
lower than 2 cm.sup.2 and most preferably lower than 0.5 cm.sup.2.
Keeping this in mind a diamond with width "W" equal to 0.6cm and
length "L" equal to 1.2cm will have an area of 0.36 cm.sup.2.
Patterns in FIGS. 19b and 19c will reduce this area to half
assuming the width of the EC areas (or stripes) to be equal to the
width of the non-EC areas (or stripes). The width of the stripes
"D" in FIGS. 21b and 21c should be preferably less than 1 mm, and
more preferably less than 500 .mu.m. The size is dependent not only
upon the targeted readout configuration but also where the shutter
is located relative to the information plane as will be discussed
in further detail below. Some of the preferred widths of the EC
regions are 15, 21, 27, 42, 228 and 456 microns. The width of the
non-EC region plus the width of the non-EC regions "P" is
preferably in the range of one to ten times "D." The EC device may
be placed in any orientation which may maximize the effectiveness
of the dark (closed) state, however, it is preferred that the total
width of the EC device cover 0.7 cm or more along a track to
generate sufficient uncorrectable errors. One preferred orientation
is for the short diamond axis in FIGS. 21b and 21C to orient along
the radial direction of the disc and be located in the lead-in area
and/or where the control data file (containing physical format
information), the ISO/UDF file structure or any other enabling data
is located. FIG. 21 only shows an example of a pattern formed by
equally spaced linear stripes. The pattern may be formed by lines
of unequal widths and spacing, may be in the form of a checker
board, or the stripes may be curved with any desirable orientation.
It will be appreciated that other patterns may be used. Further the
boundary between the EC and the non-EC area may be sharp and well
defined or it may be diffused.
[0137] Using the printing techniques one may also create watermarks
and or codes (i.e., equivalent of pits and lands) which can be read
by the machine in one state (say when the EC pattern is colored)
and not in the other state (when the EC pattern is bleached).
Preferably these patterns will have common electrodes, unless these
need to be addressed selectively. This action is similar to writing
and erasing information on a writable DVD discs where rather than
actual pits one creates areas which have different refractive index
and/or optical absorption. Thus these codes are present on the DVD
as produced and limit the access to the data, however, these are
bleached (or erased) when the DVD is legitimately activated. These
codes or data encryption/authentication schemes could be the
standard ones used in the industry such as "water marks" "content
scrambling system (CSS)", "content protection for prerecorded media
(CPPM)", "content protection for recordable media (CPRM)", "copy
generation management (CGMS)", etc. or additional schemes. Further,
there could be several protection schemes and levels of data access
corresponding to activation of different patterns as required by
the data owner. This may allow a user to purchase the same DVD for
rent or ownership, where in the former, one of the codes is erased,
and in the latter another or a second code is erased depending on
the user intention and the price paid.
[0138] As described in above paragraphs, the EC device may have a
geometry, size, pattern, orientation, and a location selected to
cause the reading laser to lose tracking or focusing lock or
distort the tightly focused reading spot. In such a way, the laser
becomes ineffective in reading data or information from the disk,
and renders the disk unusable in that reading device. In a similar
manner, it disables the disc for any writing or rewriting purposes.
By emphasizing the disturbance effects the EC device provides to
the laser, the size of the EC device may thereby be reduced, while
still disabling an unauthorized disc. Since the EC device is
smaller, the amount of current required to activate or deactivate
the EC layer is reduced. Additionally, the cost and complexity of
manufacturing the disk may also be lowered.
[0139] In general terms, the geometry, pattern, orientation
(particularly relative to the information tracks), size and
location of the EC device or the EC materials within the device,
may be designed and constructed to minimize or maximize various
"effects" or disturbances that either individually or collectively
minimize or maximize the reading or writing device's ability to
read or write to the disc. These disturbances can further be
combined with the coloring or bleaching properties of the EC device
to create an effective, and a difficult to defeat, means for
enabling or disabling access to data stored within the disc. In
addition, optimizing the geometry, pattern, orientation, size and
location of the EC materials within the EC device makes it possible
to not only create effective means for enabling or disabling access
to data stored within the disc, but also to reduce the amount of EC
material required, thus reducing material cost, lower manufacturing
yields and reduce the power and time required to switch the EC
device's state.
[0140] For example, a disc may be provided with an EC device having
an EC layer preset to make the disc unreadable. The EC layer may be
coupled to an RF frequency module which is mounted or embedded on a
disc. At a point of sale terminal, the disc is scanned with an RF
enabled point of sale terminal, and a communication is established
between the RF module and the POS terminal. The RF module may
receive an activation code, and responsive to verifying the
authenticity of the code, provide an electrical signal to clear the
EC layer. To power the electrical signal, the RF module may have,
for example, either 1) a very small battery or 2) a circuit for
converting RF energy into an electrical signal. These small power
sources must be sufficient to robustly and reliably switch the EC
layer to make the disc readable only if the EC layer is
comparatively small relative to the surface area of the disc.
[0141] The pattern, location, geometry, orientation, size and
location of the EC device, or the EC material and associated
materials in the EC stack within the EC device, can be used to
minimize the edge effects to enable error free reading of, or
writing to the disc. The pattern, location, geometry, orientation,
size and location of the EC device, or the EC material and
associated materials in the EC stack within the EC device can also
be used to induce errors which cannot be corrected by the error
correction capabilities of reading and writing devices and players
by maximizing the edge and/or distortion effects and thus making
the disc unusable without solely relying on blocking the laser
light. This may result from distorting the focus of the readout
beam or inducing spatial variation of phase, amplitude, and/or
polarization onto the readout beam. The spatial frequency or
frequencies of the EC material patterns may also be engineered to
maximum effect by making it comparable to that of readout beam size
at the point where the EC device is positioned vertically relative
to the data structures in the disc.
[0142] The error correction code in a standard DVD for example, can
enable a DVD player to recover from relatively long segments of
unreadable data tracks (up to approximately 5 mm). It is not
necessary to, for instance, completely block the interrogating read
back beam over the entire segment, as long as sufficient errors are
induced (to achieve uncorrectable errors) by altering the focused
beam properties and quality or by inducing errors in the player
servo systems to e.g. cause the beam to wander off track or
defocus. It is therefore important to carefully select the optical
properties of the EC device as well as the orientation and
placement of the boundaries of the device layers for shutter which
only covers a limited part of the accessible information stored on
the optical disc. Conversely it is also possible to exploit the
edge or boundary effects in a small EC device to introduce enough
errors so that the reading device or player's error correction
logic is not able to recover. Similar approaches can be taken for
recordable or rewritable media to induce uncorrectable errors and
make the disc unusable.
[0143] The EC device is designed, constructed, and placed to
distort or disturb light reflected from the disc. With proper
placement and orientation of the EC device, these distortions may
be controlled to generate an expected level of induced errors in a
disc reading system. This emphasis on induced error rate is a
fundamental recognition that has enabled a new type of practical
denial-of-benefit system. That is, the emphasis is not on how
effectively the EC device blocks the optical properties of the disc
itself, but now looks at the level of errors that a pattern can
induce in a laser reading system. This shift enables the disc
manufacturers, content providers, and distributors to practically
implement a protected distribution system. For example, the EC
device may have a pattern, geometry, shape, and location that
effectively makes an unauthorized DVD unreadable in every or almost
every consumer DVD player, and yet may be simply implemented at the
point of sale in a retail environment. In this way, a disc is
useless for consumer use until a retailer or approved distributor
has authorized the disc.
[0144] Referring again to the example of a DVD disc for use in
consumer DVD player. There are several mechanisms by which an EC
device in a deactivated disc may induce sufficient errors in the
reading process to render the disc unusable. For example, the EC
device may distort the laser beam to induce a stream of
non-correctable read errors. The distortion may be according to
phase, amplitude, or polarization. The distortion effect may be
adjusted or selected by the specific optical properties of the EC
material or by the size, shape, or location of the EC device. For
example, many EC materials have a profound effect on amplitude or
transmission, while other electrically activated optical shutter
materials, such as liquid crystals, have a more profound effect on
phase and polarization.
[0145] A disc may have one or more EC devices, and the EC devices
may have different sizes, shapes, or characteristics depending on
the particular application. In one application, the EC devices are
distributed about the disc surface in a pattern or such that
selective content can be blocked. In other applications, a single
EC device may be sufficient. FIG. 22 shows an example of an EC
device 150 in a colored or blocked state. The EC device 150 is
shown having a six-sided shape, although it will be appreciated
that other shapes may be used, such as circular, oval, arcing,
radial, rectangular, or irregular. The EC device is a thin film
device that uses a set of layers to selectably excite an EC layer.
The EC layer is optically sensitive, and changes an optical
property or properties when activated by an electrical signal.
Although the property typically is its opaqueness, other optical
properties may be changed. The EC material may fully cover the EC
device, or the EC material may be arranged in a pattern independent
of the electrodes (or counterelectrodes) further comprising the EC
device. As illustrated, the EC material is in the shape of two
parallel rectangles, and cover less than 50% of the EC device total
area. Although the EC material is shown as parallel bars, it will
be appreciated that many other shapes, designs, or patterns may be
used.
[0146] One or more of the layers in the EC device may be
transparent or nearly transparent. Therefore, even in areas where
there is no EC material, other transparent or non-optically
sensitive layers may be present. In use, the EC device is placed
relative to an information track on an optical disc. As generally
discussed earlier, when a disc is in an unauthorized state, the EC
device may be designed and arranged to distort the reading laser so
as to induce uncorrectable errors, thereby rendering the disc
unusable. Certain transition edges may be managed to obtain
desirable distortion effects and control. As shown above, the
information track has a transition edge with the EC device shape,
even when the EC layer does not extend to the shape's perimeter.
Also, the information track has a transition edge with the actual
EC material in the EC layer. When a pattern of EC material is used,
as illustrated above, several transition edges are defined. Each of
the transition edges has an impact on distortion, and, as will be
more fully described below, the character and level of distortion
may be controlled by adjusting the angle of the transition edge in
relation to the information track.
[0147] Transition edges may be designed and constructed to produce
desirable distortion effects. For example, a disc has a information
track that generally spirals around from the center to the outside
of the disc or vice versa. When an EC device is positioned relative
to a particular segment of the information track, a transition edge
is formed at the edge of the EC device, and if a patterned EC layer
is employed, EC material transition edges are also formed.
Depending on the orientations of the EC device and the EC material,
different distortion effects may be affected.
[0148] The orientation and placement of transition edges may be
used to control the level of generated distortion to the laser
beam. For example, the edges indicated "Edge 1" and "Edge 2" in the
FIG. 22 run predominantly parallel with the information track.
These parallel edges are typically to be avoided if designing the
transition geometry for minimum impact on tracking servo signals
and therefore best readability in the open state of the EC shutter.
Take the case where the open state optical characteristics of the
shutter are too different from that of the no shutter state. In
this design situation, the optical shutter edges should form a
large angle with the information tracks. In case of a DVD the edges
of the shutter can be completely perpendicular to the information
tracks if the shutter covers an area fully extending across the
information area in radial dimension, i.e., from radius
approximately less than 22 mm to a radius as large as approximately
58 mm. However, with a minimum length along the track of 5 mm, the
overall area is significantly larger than the desired area for
reduced power requirements discussed above. Therefore, to further
reduce the area of the shutter and at the same time keep the angles
between the edges of the shutter as large as possible with respect
to the information tracks one preferable shape of the shutter is
diamond shaped as will be further detailed below. However, as the
EC geometry/pattern affects both the open state playability and
closed state non-playability, other designs may be alternatively
applied to meet other design criteria. Take the case where an EC
shutter design has open state optical characteristics that are
virtually identical to that of the non shutter area, including
edges which are largely parallel with the information tracks. This
orientation will increase the amount of distortion for the closed
state. These principles can be applied both to the general
shape/geometry of the EC area as well as any patterns within the
geometry. Another issue related to the transitional edge is the
height of the various layers forming the EC device. These steps
created by various layers may also lead to large focusing errors in
the open state. One way of minimizing these are creating tapered
edges or a series of smaller steps rather then single steps of each
layer. The edges can be made into a tapered shape (or diffused) in
PVD processes by controlling the mask distance from the substrate,
or if printing is used by controlling surface tension between the
substrate and the printing fluid to control contact angles or using
dilute solutions around the edges.
[0149] FIG. 23 illustrate a sampling of EC device and EC patterns
that may be used on optical discs, such as a DVD. It will be
appreciated that these patterns and methods may also be applied to
other optical shutter technologies and that the selection and
details of any selected design are subject to the requirements of
the particular application. For example, each design involves
tradeoffs regarding security, cost, manufacturability, power
available during activation, and the practicalities of distribution
and sale. Although specific dimensions, shapes, and locations are
discussed, these are not intended to be limiting, but are intended
to illustrate the flexibility and wide applicability of a patterned
EC layer and device.
[0150] FIG. 23(a) shows an EC device in the general shape of a
diamond. The diamond EC pattern is positioned such that the
information track makes a large angle at the transition to the EC
device edge, the EC material, as well as edges of other associated
materials in the EC stack. The EC material is solid within the
diamond shape, so provides full blocking or distortion within the
defined area. For example, the EC material may be selected to
sufficiently block light from reading the data disk, or it may
present an optical characteristic that distorts any reflected
light. The distortion would be sufficient to induce at least one
uncorrectable error in the DVD reading system, rendering the disc
unusable. In this design, very substantial errors, resulting in at
least one uncorrectable error will be induced when the EC material
is blocked, and some errors may still be produced when the material
is bleached. Also, this design is useful when the EC material
itself has relatively low distortion effects, so when in a bleached
state, the error level is acceptable resulting in no uncorrectable
errors in the user data. In a more specific example, the EC layer
may be selected with thickness or chemical properties that produce
relatively low level of distortion.
[0151] Conditional access on DVD-9 may be affected by generating an
EC stack pattern onto the L0 semi-reflective layer in order to
block L1 access by the target player. In another arrangement,
conditional access may be affected by generating an EC stack
pattern onto the air incident side of L0 substrate in order to
block both L0 and L1 access by the target player. Other
applications and arrangements may be used. The dimensions for the
device below may be according the following table: TABLE-US-00005
Target Dimensions Target Dimensions (EC Stack onto L0 (EC Stack
onto Air Incident Semi-Reflective Layer) Side of L0 Substrate): W:
6 mm 6 mm L: 12 mm 12 mm Total EC area: 36 mm2
[0152] FIG. 23(b) shows an EC device in the general shape of a
diamond, which is filled with an EC material in a pattern. The
diamond EC device has a device edge that has a large transition
angle with the information track, minimizing any distortion effect,
such as diffraction, in the radial dimension potentially causing
tracking servo problems in the open shutter state. The EC pattern,
though, is positioned such that the information track makes a
generally orthogonal angle at the transition to the EC pattern
material, fully minimizing any distortion effect in the radial
dimension. The EC pattern material is generally arranged as a
series of parallel bars, confined by the general diamond device
edge. This arrangement allows less EC material to be used in
contrast to the solid pattern in the above figure. For example, the
device below may be constructed using only 18 mm2 of EC material,
as compared to 36 mm2 for the device illustrated above. Also, since
the information track has an orthogonal relationship with the long
axis of the EC bars, less distortion may be generated when the EC
material is bleached. It will also be appreciated that the
individual bars may have different properties, which may further
induce errors. However, as illustrated in the figure below, each of
the bars is of a like EC material. The width and duty cycle (fill
factor) of the bars depend on the size of the interrogating read
beam at the position of the shutter in relation to the information
layer in the direction substantially orthogonal to the information
layer (and parallel to the propagation direction of the read out
beam). In particular, the size of the beam depends primarily on the
wavelength of the readout beam, the numerical aperture of the read
out optic, and the distance between shutter and information layer.
It should be noted that patterns can be preferably designed to
affect the read out beam for several combinations of wavelengths
and/or numerical apertures. The various feature sizes can be
incorporated into one shutter or included in separate shutters or
any combination thereof This scheme can be particularly useful for
assuring adequate blocking performance of a DVD shutter by also
designing for shorter wavelengths operation, such as 405 nm, used
by emerging higher density players (HD-DVD or Blu-ray Disc
players). The EC materials must of course also be designed for
multi-wavelength operation. For example, bars may be of smaller
width when the EC layer is disposed within the disc and close to
the information track as the cross-section of the converging cone
of light from the readout device at which it intersects the EC
device is relatively small. Generally, the width of the bars may be
adjusted according to the size of the readout light as it passes
through the EC device. Accordingly, the closer the EC layer is to
the information layer to be blocked, the smaller the width of the
bars may be designed to generate the desired level of distortion.
As DVD players more or less require the same "cone" of light to
read out the disc (same numerical aperture of the lens) this
method/configuration has a similar effect on all players (using the
same readout wavelength). Reducing the frequency of these bars in
addition to reducing the overall active area may also adversely
affect the servo performance of the player by interfering with
focus, tracking, HF slicer, AGC (automatic gain control) circuitry,
or other player functions. In this way, a smaller amount of EC
material may be used to achieve sufficient levels of distortion to
render a disc unusable. As servos are implemented differently by
different player manufacturers it will be appreciated that the
effect can be very player dependent.
[0153] The dimensions for the device below may be according the
following table: TABLE-US-00006 Target Dimensions Target Dimensions
(EC Stack onto L0) (EC Stack onto Air Incident Semi-Reflective
Layer) Side of L0 Substrate): W: 6 mm 6 mm L: 12 mm 12 mm D: 21
.mu.m, 15 .mu.m, 27 .mu.m,42 .mu.m, & 456 .mu.m 228 .mu.m, 456
.mu.m P: 2*D 2*D Total EC area: 18 mm2
[0154] FIG. 23(c) illustrates another EC device with a lower
density of EC pattern material. The device edge and EC pattern are
similar to the device and pattern described above, so will not be
discussed in detail. This design may be applicable to a
construction where even less EC material is employed. Depending on
the EC material properties this design can induce similar errors at
is the case above, but at half of the EC area. In this way,
substantially less material is needed, and may be activated using
far less power.
[0155] The dimensions for the device below may be according the
following table: TABLE-US-00007 Target Dimensions Target Dimensions
(EC Stack onto L0 (EC Stack onto Air Incident Semi-Reflective
Layer) Side of L0 Substrate): W: 6 mm 6 mm L: 12 mm 12 mm D: 21
.mu.m, 15 .mu.m, 27 .mu.m, 42 .mu.m, & 456 .mu.m 228 .mu.m, 456
.mu.m P: 2*D 2*D Total EC area: 9 mm2
[0156] FIG. 23(d) illustrates another EC device with an even lower
density of EC pattern material. The device edge and EC pattern is
similar to the device and pattern described above, so will not be
discussed in detail. This design may be applicable to a
construction where even less EC material is employed. Depending on
the EC material properties this design can induce similar errors at
is the case above, but at half of the EC area. In this way,
substantially less material is needed, and may be activated using
far less power.
[0157] The dimensions for the device below may be according the
following table: TABLE-US-00008 Target Dimensions Target Dimensions
(EC Stack onto L0 (EC Stack onto Air Incident Semi-Reflective
Layer) Side of L0 Substrate): W: 6 mm 6 mm L: 12 mm 12 mm D: 21
.mu.m, 15 .mu.m, 27 .mu.m, 42 .mu.m, & 456 .mu.m 228 .mu.m, 456
.mu.m P: 2*D 2*D Total EC area: 4.5 mm2
[0158] FIG. 23(e) shows an EC device in the general shape of a
diamond. The EC device is filled with an EC material in a pattern.
The EC material is generally arranged as a series of parallel bars,
confined by a general diamond device edge. The parallel bars of the
EC material have long edges that have a large transition angle with
the information track thus inducing more distortion than an
orthogonal edge transition. This arrangement allows less EC
material to be used in contrast to a solidly filled EC device. For
example, the device below may be constructed using only 18 mm2 of
EC material, as compared to 36 mm2 for a solid pattern. Of course,
as previously discussed, some level of distortion may also be
generated when the EC material is bleached, and the level of
distortion is likely to be greater than in the case where the EC
material was orthogonal to the information track. Accordingly, the
EC material and the target will have to limit the level of induced
errors to a correctable level in the target device. It will also be
appreciated that the individual bars may have different properties,
which may further induce errors. However, as illustrate in the
figure below, each of the bars is of a like EC material. The
distance between bars may be selected according to several factors
in a similar way as discussed above for the perpendicular bars. For
example, bars may be spaced closer together when the EC layer is
disposed within the disc and close to the information track. In
this arrangement, additional bars may be needed to induce
sufficient errors, as the bars are relatively close to the focus
point of the laser.
[0159] The dimensions for the device below may be according the
following table: TABLE-US-00009 Target Dimensions Target Dimensions
(EC Stack onto L0 (EC Stack onto Air Incident Semi-Reflective
Layer) Side of L0 Substrate): W: 6 mm 6 mm L: 12 mm 12 mm D: 21
.mu.m, 15 .mu.m, 27 .mu.m, 42 .mu.m, & 456 .mu.m 228 .mu.m, 456
.mu.m 2*D 2*D Total EC area: l8 mm2
[0160] FIG. 23(f) illustrates another EC device with a lower
density of EC pattern material. The device edge and EC pattern is
similar to the device and pattern described above, so will not be
discussed in detail. This design may be applicable to a
construction where even less EC material is employed. Depending on
the EC material properties this design can induce similar errors at
is the case above, but at half of the EC FIG. 25 area. In this way,
substantially less material is needed, and may be activated using
far less power.
[0161] The dimensions for the device below may be according the
following table: TABLE-US-00010 Target Dimensions Target Dimensions
(EC Stack onto L0 (EC Stack onto Air Incident Semi-Reflective
Layer) Side of L0 Substrate): W: 6 mm 6 mm L: 12 mm 12 mm D: 21
.mu.m, 15 .mu.m, 27 .mu.m, 42 .mu.m, & 456 .mu.m 228 .mu.m, 456
.mu.m P: 2*D 2*D Total EC area: 9 mm2
[0162] FIG. 23(g) illustrates another EC device with an even lower
density of EC material. The EC device and pattern are similar to
the device and pattern described above, so will not be discussed in
detail. This design may be applicable to a construction where even
less EC material is employed. Depending on the EC material
properties this design can induce similar errors at is the case
above, but at half of the EC area. In this way, substantially less
material is needed, and may be activated using far less power.
[0163] The dimensions for the device below may be according the
following table: TABLE-US-00011 Target Dimensions Target Dimensions
(EC Stack onto L0 (EC Stack onto Air Incident Semi-Reflective
Layer) Side of L0 Substrate): W: 6 mm 6 mm L: 12 mm 12 mm D: 21
.mu.m, 15 .mu.m, 27 .mu.m, 42 .mu.m, & 456 .mu.m 228 .mu.m, 456
.mu.m P: 2*D 2*D Total EC area: 4.5 mm2
[0164] In FIG. 23, certain exemplary dimensions and sizes were
given. The listed dimensions and sizes are for illustrative
purposes only, and other sizes, shapes, dimensions, and relative
dimensions may be used. For example, the EC Device was identified
as being about 36 mm2, and the overall EC area as being in the
range from 4.5 mm2 to 36 mm2. It will be appreciated that some
applications may be enabled using smaller EC devices, and less
overall EC area. It will be appreciated that the effect of the EC
device may be advantageously applied to different areas of a
typical DVD disc. For example, a typical DVD disc has an index and
menu area that must be accessible for the disc to operate in the
typical DVD player. In this way, it is not necessary to induce
errors across the entire disc surface, but only in this limited
index and menu area. Accordingly, a limited area of an EC pattern
may effectively disable disc access in the typical consumer DVD
player.
[0165] A disk may also be constructed with multiple patterns in one
or multiple EC devices, with each pattern selected to induce errors
in a somewhat different way. In this way, patterns may cooperate to
generate an array of read errors that may further confound laser
reading systems. Also, by combining such patterns, and overall
smaller EC area may be used, which can be transitioned with less
power. It will also be appreciated that as consumer's DVD players
advance, different circuits and processes for reacting to the EC
material and its associated transition line may be used. For
example, future players may reduce their time to refocus, speed the
time to re-establish tracking, or increase tolerance to distortion
errors. Discs may therefore include EC devices and patterns for
inducing uncorrectable errors for these expected advancements.
[0166] It should be noted that the foregoing embodiments are merely
examples and are not to be construed as limiting the invention. The
description of the embodiments is intended to be illustrative, and
not to limit the scope of the claims. As such, the present
teachings can be readily applied to other types of devices and many
alternatives, modifications, and variations will be apparent to
those skilled in the art
* * * * *
References